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Purpose: The use of anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CART) therapy for AL amyloidosis (AL) is limited owing to patient frailty. HBI0101 anti-BCMA CART was the first proof of concept for its applicability to AL. This report addresses the AL patient cohort treated to date within the phase Ia/Ib clinical trial (ClinicalTrials.gov identifier: NCT04720313)., Methods: After lymphodepletion, most AL patients were infused with 800 × 10 6 CARTs., Results: Sixteen patients were treated, with a median of four previous lines of therapy (range, 3-10), 14/16 were triple class refractory, and 6/16 were refractory to belantamab. Most patients (13/16) had cardiac involvement, including five with MAYO stage IIIa/IIIb at study entry. Cytokine release syndrome was frequent (14/16) but mostly low grade (grade 3: 3/16, no grade 4/5). No neurologic toxicity or treatment-related deaths were observed. There were five grade 3 AL-related organ deteriorations resolved quickly with supportive care. The overall hematologic response rate was 15/16 (94%) and complete response (CR) was 12/16 (75%). Minimal residual disease negativity was achieved in 9/14 evaluable patients. Most patients (8/13 evaluable) achieved an objective organ response. Seven patients died during long-term follow-up, three while in CR/very good partial response, and the median overall survival was 10.1 months (95% CI, 5.8 to not reached)., Conclusion: This largest clinical trial of AL patients treated with anti-BCMA CART demonstrates acceptable and manageable toxicity in a highly frail and resistant population with remarkable efficacy, leading to fast organ responses. Among patients with baseline advanced cardiac disease, deaths in the first year were frequent, suggesting that this effective therapy should be considered earlier in the course of therapy. Anti-BCMA CART may become a powerful tool for improving organ function and survival in patients with AL.

Abstract: HBI0101 is an academic chimeric antigen receptor T-cell (CART)-targeted to B-cell maturation antigen (BCMA) for the treatment of relapsed and refractory multiple myeloma (R/RMM) and light chain amyloidosis. Herein, we present the phase 1b/2 results of 50 heavily pretreated patients with R/RMM dosed with 800 × 106 CART cells. Inclusion criteria were relatively permissive (i.e., performance status and baseline organ function) and consequently, approximately half of the enrolled patients would have been ineligible for pivotal clinical trials. The median time elapsed from patient enrollment until CART delivery was 25 days (range, 14-65). HBI0101-related toxicities included grade 1 to 3 cytokine release syndrome, grade 3 to 4 hematologic toxicities, and grade 1 to 2 immune effector cell-associated neurotoxicity syndrome. Responses were achieved in 90% of the patients, 56% achieved stringent and complete response, and 70% reached a minimal residual disease negativity. Within a median follow-up of 12.3 months, the median progression-free survival (PFS) was 11.0 months (95% confidence interval [CI], 6.2-14.6), and the overall survival was not reached (95% CI, 13.3 to not reached). Multivariable analysis on patient/disease and CART-related characteristics revealed that high-risk cytogenetic, extramedullary disease, and increased number of effector-memory T cells in CART products were independently associated with inferior PFS. In conclusion, comprehensive analyses of the parameters affecting the response to CART therapy are essential for improving patients' outcome. This trial was registered at www.ClinicalTrials.gov as #NCT04720313., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Purpose: Although chimeric antigen receptor T therapy (CAR-T) cells are an established therapy for relapsed/refractory multiple myeloma (RRMM), there are no established models predicting outcome to identify patients who may benefit the most from CAR-T., Patients and Methods: This is an international retrospective observational study including patients with RRMM infused with currently available commercial or academically produced anti-B-cell maturation antigen (BCMA) CAR-T. We describe characteristics and outcomes in Europe (n = 136) and the United States (n = 133). Independent predictors of relapse/progression built a simple prediction model (Myeloma CAR-T Relapse [MyCARe] model) in the training cohort (Europe), which was externally validated (US cohort) and tested within patient- and treatment-specific subgroups., Results: The overall response rate was 87% and comparable between both cohorts, and complete responses were seen in 48% (Europe) and 49% (the United States). The median time to relapse was 5 months, and early relapse <5 months from infusion showed poor survival across cohorts, with the 12-month overall survival of 30% (Europe) and 14% (the United States). The presence of extramedullary disease or plasma cell leukemia, lenalidomide-refractoriness, high-risk cytogenetics, and increased ferritin at the time of lymphodepletion were independent predictors of early relapse or progression. Each factor received one point, forming the three-tiered MyCARe model: scores 0-1 (low risk), scores 2-3 (intermediate risk), and a score of 4 (high risk). The MyCARe model was significantly associated with distinct 5-month incidence of relapse/progression ( P < .001): 7% for low-risk, 27% for intermediate-risk, and 53% for high-risk groups. The model was validated in the US cohort and maintained prognostic utility for response, survival, and outcomes across subgroups., Conclusion: Outcomes of patients with RRMM after CAR-T are comparable between Europe and the United States. The MyCARe model may facilitate optimal timing of CAR-T cells in patient-specific subgroups.

Multiple myeloma (MM) is characterized by recurrent relapses. Consequently, patients receive multiple therapy lines, including alkylating agents and immune modulators, which have been associated with secondary malignancies such as myelodysplastic syndrome (MDS). Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T cell (CART) therapy is efficacious in patients with relapsed/refractory (R/R) MM. However, the long-term complications, particularly MDS, are not well understood. Whether CART therapy causes or promotes MDS has not been thoroughly investigated. In this study, we explored the causal relationship between MDS and CART therapy. We retrospectively examined the prevalence of MDS-related morphological and mutational changes before and after administration of CART therapy in five patients. Among them, four developed MDS after CART therapy, while one had pre-existing MDS prior to CART. None of the four patients who developed post-CART MDS showed morphological MDS changes prior to CART therapy. However, all four patients exhibited molecular alterations associated with MDS in their pre-CART as well as post-CART therapy bone marrow. No new mutations were observed. Our findings provide initial evidence suggesting that anti-BCMA CART therapy in MM may promote expansion of pre-existing MDS clones rather than causing development of new clones.

Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CAR T) therapy shows remarkable efficacy in patients with relapsed and/or refractory (R/R) multiple myeloma (MM). HBI0101, a novel second generation optimized anti- BCMA CAR T-cell therapy, was developed in an academic setting. We conducted a phase I dose-escalation study of HBI0101 (cohort 1: 150x106 CAR T cells, n=6; cohort 2: 450x106 CAR T cells, n=7; cohort 3: 800x106 CAR T cells, n=7) in 20 heavily pre-treated R/R MM patients. Grade 1-2 cytokine release syndrome (CRS) was reported in 18 patients (90%). Neither grade 3-4 CRS nor neurotoxicity of any grade were observed. No dose-limiting toxicities were observed in any cohort. The overall response rate (ORR), (stringent) complete response (CR/sCR), and very good partial response rates were 75%, 50%, and 25%, respectively. Response rates were dose-dependent with 85% ORR, 71% CR, and 57% minimal residual disease negativity in the high-dose cohort 3. Across all cohorts, the median overall survival (OS) was 308 days (range 25-466+), with an estimated OS of 55% as of June 27th (data cut-off). The median progression-free survival was 160 days, with 6 subjects remaining progression free at the time of data cut-off. Our findings demonstrate the manageable safety profile and efficacy of HBI0101. These encouraging data support the decentralization of CAR T production in an academic setting, ensuring sufficient CAR T supply to satisfy the increasing local demand. Clinicaltrials.gov NCT04720313.

Purpose: AL amyloidosis (AL) treatments are generally based on those employed for multiple myeloma. Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T (CART)-cell therapy, already approved for multiple myeloma, might be too toxic for patients with AL., Experimental Design: Here we describe the ex vivo applicability of a novel in-house, academic anti-BCMA CAR construct on AL primary cells, as well as the safety and efficacy in 4 patients with relapsed/refractory (RR) primary AL, treated in a phase I clinical trial (NCT04720313)., Results: Three had MAYO stage IIIa cardiac involvement at enrollment. The treatment proved relatively safe, with a short and manageable grade 3 cytokine release syndrome evident in 2 patients and no neurotoxicity in any. Cardiac decompensations, observed in 2 patients, were also short and manageable. The overall hematologic response and complete response rates were observed in all patients with an organ response evident in all four. Within a median follow-up period of 5.2 (2.5-9.5) months, all 4 patients maintained their responses., Conclusions: BCMA-CART cells provide a first proof-of-concept that this therapy is safe enough and highly efficacious for the treatment of patients with advanced, RR AL., (©2022 American Association for Cancer Research.)

Chimeric antigen receptor (CAR) T-cell based immunotherapy has become a promising treatment mainly for hematological malignancies. Following the major success of CD19-targeted CAR, new potential targets for other malignancies are required. As such, B-cell maturation antigen (BCMA) is an attractive tumor-associated antigen to be targeted in multiple myeloma (MM). Herein, we aimed at assessing the function and optimal configuration of different BCMA-specific CAR, based on the same targeting moiety but with a different hinge and co-stimulatory domain. We compared their function to that of a previously characterized BCMA-CAR used in clinical trials. All constructs were expressed at high levels by primary human T cells and could trigger cytokine production and cytotoxicity upon co-culture with multiple myeloma targets. Nonetheless, critical differences were observed in off-target activation, exhaustion, and activation marker expression and in vivo antitumoral activity mediated by these different constructs. Interestingly, we noted that CD8-based hinge, combined with a 4-1BB intracellular domain, proved superior compared to IgG4-connecting regions, and/or a CD28-signaling moiety respectively. Overall, this study emphasizes the influence of CAR primary structure on its function and led to the identification of a highly efficient BCMA-specific CAR, namely H8BB, which displayed superior anti-tumoral activity both in vitro and long-term in vivo efficacy.

The GTPase of immunity-associated proteins (GIMAPs) are a family of genes believed to contribute to lymphocyte development, signaling, and apoptosis, thus playing an important role in immune system homeostasis. While models of gene derangement have been described in both mice and immortalized cell lines, human examples of these diseases remain exceptionally rare. In this manuscript we describe the first documented human cases of a homozygous deleterious GIMAP6 variant in the GIMAP6 gene and their subsequent clinical and immunological phenotype. In order to interrogate the patients' immune defect, we performed whole-exome sequencing, western blot, flow cytometry analysis, lymphocyte activation and proliferation studies, cytokine release assays, and apoptosis studies. We found two siblings with a predicted deleterious homozygous variant in the GIMAP6 gene with no expression of GIMAP6 protein on western blot. Patients demonstrated accelerated apoptosis, but largely normal lymphocyte subpopulations, activation and proliferation and cytokine release. There appears to be a spectrum of clinical features associated with deficiency of GIMAP6 protein, with one patient suffering lymphopenia and recurrent sinopulmonary infections, and the other clinically asymptomatic. Biallelic variants in the GIMAP6 gene have now been shown to demonstrate disease in humans. The absence of GIMAP6 protein is associated with a spectrum of clinical manifestations and much remains to be learnt about the pathogenic mechanisms underlying this disease. We suggest that biallelic variants in the gene for GIMAP6 should be considered in children with lymphopenia and recurrent sinopulmonary infections.

Mutations in the VPS45 gene lead to a severe primary immune deficiency characterized by severe congenital neutropenia and primary myelofibrosis, leading to overwhelming infection and early death. This condition is exceedingly rare with only 16 patients previously reported, including four with successful hematopoietic stem cell transplantation. We review the pathophysiology underlying this condition and detail our approach to treatment, particularly vis-à-vis bone marrow transplantation and the challenges of transplanting into a diseased bone marrow niche. We provide an update on the progress of our three previously reported patients, and two additional patients transplanted at our center., (© 2018 Wiley Periodicals, Inc.)

Protein solubility determines the conditions under which the protein will remain in solution. As a result, it is an important quantity in applications that involve concentrated protein solutions. Here I describe the solubility measurement of the protein thaumatin in the presence of tartrate ions as a function of temperature. This method can be used to measure the solubility of other proteins.

Glucocorticoid (GC) hormones are an important ingredient of leukemia therapy since they are potent inducers of lymphoid cell apoptosis. However, the development of GC resistance remains an obstacle in GC-based treatment. In the present investigation we found that miR-103 is upregulated in GC-sensitive leukemia cells treated by the hormone. Transfection of GC resistant cells with miR-103 sensitized them to GC induced apoptosis (GCIA), while miR-103 sponging of GC sensitive cells rendered them partially resistant. miR-103 reduced the expression of cyclin dependent kinase (CDK2) and its cyclin E1 target, thereby leading to inhibition of cellular proliferation. miR-103 is encoded within the fifth intron of PANK3 gene. We demonstrate that the GC receptor (GR) upregulates miR-103 by direct interaction with GC response element (GRE) in the PANK3 enhancer. Consequently, miR-103 targets the c-Myc activators c-Myb and DVL1, thereby reducing c-Myc expression. Since c-Myc is a transcription factor of the miR-17~92a poly-cistron, all six miRNAs of the latter are also downregulated. Of these, miR-18a and miR-20a are involved in GCIA, as they target GR and BIM, respectively. Consequently, GR and BIM expression are elevated, thus advancing GCIA. Altogether, this study highlights miR-103 as a useful prognostic biomarker and drug for leukemia management in the future.

CD44 is a multi-functional receptor with multiple of isoforms engaged in modulation of cell trafficking and transmission of apoptotic signals. We have previously shown that injection of anti-CD44 antibody into NOD mice induced resistance to type 1 diabetes (T1D). In this communication we describe our efforts to understand the mechanism underlying this effect. We found that CD44-deficient NOD mice develop stronger resistance to T1D than wild-type littermates. This effect is not explained by the involvement of CD44 in cell migration, because CD44-deficient inflammatory cells surprisingly had greater invasive potential than the corresponding wild type cells, probably owing to molecular redundancy. We have previously reported and we show here again that CD44 expression and hyaluronic acid (HA, the principal ligand for CD44) accumulation are detected in pancreatic islets of diabetic NOD mice, but not of non-diabetic DBA/1 mice. Expression of CD44 on insulin-secreting β cells renders them susceptible to the autoimmune attack, and is associated with a diminution in β-cells function (e.g., less insulin production and/or insulin secretion) and possibly also with an enhanced apoptosis rate. The diabetes-supportive effect of CD44 expression on β cells was assessed by the TUNEL assay and further strengthened by functional assays exhibiting increased nitric oxide release, reduced insulin secretion after glucose stimulation and decreased insulin content in β cells. All these parameters could not be detected in CD44-deficient islets. We further suggest that HA-binding to CD44-expressing β cells is implicated in β-cell demise. Altogether, these data agree with the concept that CD44 is a receptor capable of modulating cell fate. This finding is important for other pathologies (e.g., cancer, neurodegenerative diseases) in which CD44 and HA appear to be implicated.

Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2,4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozyme and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.

A lighthearted researcher and a disheartened student discuss the challenges of protein crystallization and how phase diagrams can be used to address these challenges. The student feels a little better afterwards, but many proteins remain uncrystallized.

Platinum dendrimer-encapsulated nanoparticles (DENs) containing an average 147 atoms were prepared within sixth-generation, hydroxyl-terminated poly(amidoamine) dendrimers (G6-OH). The hydrodynamic radii (R(h)) of the dendrimer/nanoparticle composites (DNCs) were determined by quasi-elastic light scattering (QLS) at high (pH ∼10) and neutral pH for various salt concentrations and identities. At high pH, the size of the DNC (R(h) ∼4 nm) is close to that of the empty dendrimer. At neutral pH, the size of the DNC approximately doubles (R(h) ∼8 nm) whereas that of the empty dendrimer remains unchanged. Changes in ionic strength also alter the size of the DNCs. The increase in size of the DNC is likely due to electrostatic interactions involving the metal nanoparticle.

Toward our goal of using supercritical fluids to study solvent effects in physical and chemical phenomena, we develop a method to spatially define the solvent local number density at the solute in the highly compressible regime of a supercritical fluid. Experimentally, the red shift of the pyrazine n-pi* electronic transition was measured at high dilution in supercritical xenon as a function of pressure from 0 to approximately 24 MPa at two temperatures: one (293.2 K) close to the critical temperature and the other (333.2 K) remote. Computationally, several representative stationary points were located on the potential surfaces for pyrazine and 1, 2, 3, and 4 xenons at the MP2/6-311++G(d,p)/aug-cc-pVTZ-PP level. The vertical n-pi* ((1)B(3u)) transition energies were computed for these geometries using a TDDFT/B3LYP/DGDZVP method. The combination of experiment and quantum chemical computation allows prediction of supercritical xenon bulk densities at which the pyrazine primary solvation shell contains an average of 1, 2, 3, and 4 xenon molecules. These density predictions were achieved by graphical superposition of calculated shifts on the experimental shift versus density curves for 293.2 and 333.2 K. Predicted bulk densities are 0.50, 0.91, 1.85, and 2.50 g cm(-3) for average pyrazine primary solvation shell occupancy by 1, 2, 3, and 4 xenons at 293.2 K. Predicted bulk densities are 0.65, 1.20, 1.85, and 2.50 g cm(-3) for average pyrazine primary solvation shell occupancy by 1, 2, 3, and 4 xenons at 333.2 K. These predictions were evaluated with classical Lennard-Jones molecular dynamics simulations designed to replicate experimental conditions at the two temperatures. The average xenon number within 5.0 A of the pyrazine center-of-mass at the predicted densities is 1.3, 2.1, 3.0, and 4.0 at both simulation temperatures. Our three-component method-absorbance measurement, quantum chemical prediction, and evaluation of prediction with classical molecular dynamics simulation-therefore has a high degree of internal consistency for a system in which the intermolecular interactions are dominated by dispersion forces.

The P23T mutation in the human gammaD-crystallin gene has in recent years been associated with a number of well known cataract phenotypes. To understand the molecular mechanism of lens opacity caused by this mutation, we expressed human gammaD-crystallin (HGD), the P23T mutant, and other related mutant proteins in Escherichia coli and compared the structures and thermodynamic properties of these proteins in vitro. The results show that the cataract-causing mutation P23T does not exhibit any significant structural change relative to the native protein. However, in marked contrast to the native protein, the mutant shows a dramatically lowered solubility. The reduced solubility results from the association of the P23T mutant to form a new condensed phase that contains clusters of the mutant protein. The monomer-cluster equilibrium is represented by a solubility curve in the phase diagram. When the solubility limit is exceeded, the mutant protein forms the condensed phase after a nucleation time of 10-20 min. We found that the solubility of the P23T mutant exhibits an inverse dependence on temperature, i.e., the protein clusters are increasingly soluble as the temperature of the solution decreases. The solubility of P23T can be substantially altered by the introduction of specific mutations at or in the immediate vicinity of residue 23. We examined the mutants P23S, P23V, P23TInsP24, and P23TN24K and found that the latter two mutations can restore the solubility of the P23T mutant. These findings may help develop a strategy for the rational design of small molecule inhibitors of this type of condensed phase.

It is generally assumed that crystallization begins with a small, crystalline nucleus. For proteins this paradigm may not be valid. Our numerical simulations show that under conditions typically used to produce protein crystals, small clusters of model proteins (particles with short-range, attractive interactions) cannot maintain a crystalline structure. Protein crystal nucleation is therefore an indirect, two-step process. A nucleus first forms and grows as a disordered, liquid-like aggregate. Once the aggregate grows beyond a critical size (about a few hundred particles) crystal nucleation becomes possible.

Several human cataracts have been linked to mutations in the gamma crystallin gene. One of these is the aculeiform cataract, which is caused by an R58H mutation in gammaD crystallin. We have shown previously that this cataract is caused by crystallization of the mutant protein, which is an order of magnitude less soluble than the wild-type. Here, we report the very high-resolution crystal structures of the mutant and wild-type proteins. Both proteins crystallize in the same space group and lattice. Thus, a strict comparison of the protein-protein and protein-water intermolecular interactions in the two crystal lattices is possible. Overall, the differences between the mutant and wild-type structures are small. At position 58, the mutant protein loses the direct ion-pair intermolecular interaction present in the wild-type, due to the differences between histidine and arginine at the atomic level; the interaction in the mutant is mediated by water molecules. Away from the mutation site, the mutant and wild-type lattice structures differ in the identity of side-chains that occupy alternate conformations. Since the interactions in the crystal phase are very similar for the two proteins, we conclude that the reduction in the solubility of the mutant is mainly due to the effect of the R58H mutation in the solution phase. The results presented here are also important as they are the first high-resolution X-ray structures of human gamma crystallins.

We have studied the effect of polyethylene glycol (PEG) on the liquid-liquid phase separation (LLPS) of aqueous solutions of bovine gammaD-crystallin (gammaD), a protein in the eye lens. We observe that the phase separation temperature increases with both PEG concentration and PEG molecular weight. PEG partitioning, which is the difference between the PEG concentration in the two coexisting phases, has been measured experimentally and observed to increase with PEG molecular weight. The measurements of both LLPS temperature and PEG partitioning in the ternary gammaD-PEG-water systems are used to successfully predict the location of the liquid-liquid phase boundary of the binary gammaD-water system. We show that our LLPS measurements can be also used to estimate the protein solubility as a function of the concentration of crystallizing agents. Moreover, the slope of the tie-lines and the dependence of LLPS temperature on polymer concentration provide a powerful and sensitive check of the validity of excluded volume models. Finally, we show that the increase of the LLPS temperature with PEG concentration is due to attractive protein-protein interactions.

The cysteine residues of the gamma crystallins, a family of ocular lens proteins, are involved in the aggregation and phase separation of these proteins. Both these phenomena are implicated in cataract formation. We have used bovine gammaB crystallin as a model system to study the role of the individual cysteine residues in the aggregation and phase separation of the gamma crystallins. Here, we compare the thermodynamic and kinetic behavior of the recombinant wild-type protein (WT) and the Cys18 to Ser (C18S) mutant. We find that the solubilities of the two proteins are similar. The kinetics of crystallization, however, are different. The WT crystallizes slowly enough for the metastable liquid-liquid coexistence to be easily observed. C18S, on the other hand, crystallizes rapidly; the metastable coexisting liquid phases of the pure mutant do not form. Nevertheless, the coexistence curve of C18S can be determined provided that crystallization is kinetically suppressed. In this way we found that the coexistence curve coincides with that of the WT. Despite the difference in the kinetics of crystallization, the two proteins were found to have the same crystal forms and almost identical X-ray structures. Our results demonstrate that even conservative point mutations can bring about dramatic changes in the kinetics of crystallization. The implications of our findings for cataract formation and protein crystallization are discussed., (Copyright 2001 Academic Press.)

Several human genetic cataracts have been linked recently to point mutations in the gammaD crystallin gene. Here we provide a molecular basis for lens opacity in two genetic cataracts and suggest that the opacity occurs because of the spontaneous crystallization of the mutant proteins. Such crystallization of endogenous proteins leading to pathology is an unusual event. Measurements of the solubility curves of crystals of the Arg-58 to His and Arg-36 to Ser mutants of gammaD crystallin show that the mutations dramatically lower the solubility of the protein. Furthermore, the crystal nucleation rate of the mutants is enhanced considerably relative to that of the wild-type protein. It should be noted that, although there is a marked difference in phase behavior, there is no significant difference in protein conformation among the three proteins.

In a recent paper, patients with a progressive juvenile-onset hereditary cataract have been reported to have a point mutation in the human gammaD crystallin gene (Stephan, D. A., Gillanders, E., Vanderveen, D., Freas-Lutz, D., Wistow, G., Baxevanis, A. D., Robbins, C. M., VanAuken, A., Quesenberry, M. I., Bailey-Wilson, J., et al. (1999) Proc. Natl. Acad. Sci. USA 96, 1008-1012). This mutation results in the substitution of Arg-14 in the native protein by a Cys residue. It is not understood how this mutation leads to cataract. We have expressed recombinant wild-type human gammaD crystallin (HGD) and its Arg-14 to Cys mutant (R14C) in Escherichia coli and show that R14C forms disulfide-linked oligomers, which markedly raise the phase separation temperature of the protein solution. Eventually, R14C precipitates. In contrast, HGD slowly forms only disulfide-linked dimers and no oligomers. These data strongly suggest that the observed cataract is triggered by the thiol-mediated aggregation of R14C. The aggregation profiles of HGD and R14C are consistent with our homology modeling studies that reveal that R14C contains two exposed cysteine residues, whereas HGD has only one. Our CD, fluorescence, and differential scanning calorimetric studies show that HGD and R14C have nearly identical secondary and tertiary structures and stabilities. Thus, contrary to current views, unfolding or destabilization of the protein is not necessary for cataractogenesis.

Protein crystallization, aggregation, liquid-liquid phase separation, and self-assembly are important in protein structure determination in the industrial processing of proteins and in the inhibition of protein condensation diseases. To fully describe such phase transformations in globular protein solutions, it is necessary to account for the strong spatial variation of the interactions on the protein surface. One difficulty is that each globular protein has its own unique surface, which is crucial for its biological function. However, the similarities amongst the macroscopic properties of different protein solutions suggest that there may exist a generic model that is capable of describing the nonuniform interactions between globular proteins. In this paper we present such a model, which includes the short-range interactions that vary from place to place on the surface of the protein. We show that this aeolotopic model [from the Greek aiolos ("variable") and topos ("place")] describes the phase diagram of globular proteins and provides insight into protein aggregation and crystallization.

The self-assembly of helical ribbons is examined in a variety of multicomponent enantiomerically pure systems that contain a bile salt or a nonionic detergent, a phosphatidylcholine or a fatty acid, and a steroid analog of cholesterol. In almost all systems, two different pitch types of helical ribbons are observed: high pitch, with a pitch angle of 54 +/- 2 degrees, and low pitch, with a pitch angle of 11 +/- 2 degrees. Although the majority of these helices are right-handed, a small proportion of left-handed helices is observed. Additionally, a third type of helical ribbon, with a pitch angle in the range 30-47 degrees, is occasionally found. These experimental findings suggest that the helical ribbons are crystalline rather than liquid crystal in nature and also suggest that molecular chirality may not be the determining factor in helix formation. The large yields of helices produced will permit a systematic investigation of their individual kinetic evolution and their elastic moduli.