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Polyether ether ketone (PEEK) is gaining recognition as a highly promising polymer for orthopedic implants, attributed to its exceptional biocompatibility, ease of processing, and radiation resistance. However, its long‐term in vivo application faces challenges, primarily due to suboptimal osseointegration from postimplantation inflammation and immune reactions. Consequently, biofunctionalization of PEEK implant surfaces emerges as a strategic approach to enhance osseointegration and increase the overall success rates of these implants. In our research, we engineered a multifaceted PEEK implant through the in situ integration of chitosan‐coated zinc‐doped bioactive glass nanoparticles (Zn‐BGNs). This novel fabrication imbues the implant with immunomodulatory capabilities while bolstering its osseointegration potential. The biofunctionalized PEEK composite elicited several advantageous responses; it facilitated M2 macrophage polarization, curtailed the production of inflammatory mediators, and augmented the osteogenic differentiation of bone marrow mesenchymal stem cells. The experimental findings underscore the vital and intricate role of biofunctionalized PEEK implants in preserving normal bone immunity and metabolism. This study posits that utilizing chitosan‐BGNs represents a direct and effective method for creating multifunctional implants. These implants are designed to facilitate biomineralization and immunomodulation, making them especially apt for orthopedic applications. [ABSTRACT FROM AUTHOR]

This paper concentrates on a priori error estimates of two monolithic schemes for Biot's consolidation model based on the three‐field formulation introduced by Oyarzúa et al. (SIAM J Numer Anal, 2016). The spatial discretizations are based on the Taylor–Hood finite elements combined with Lagrange elements for the three primary variables. We employ two different schemes to discretize the time domain. One uses the backward Euler method, and the other applies the combination of the backward Euler and Crank‐Nicolson methods. A priori error estimates show that both schemes are unconditionally convergent with optimal error orders. Detailed numerical experiments are presented to validate the theoretical analysis. [ABSTRACT FROM AUTHOR]

We are concerned with the mathematical study of the mean field games system (MFGS). In the conventional setup, the MFGS is a system of two coupled nonlinear parabolic partial differential equation (PDE)s of the second order in a backward–forward manner, namely, one terminal and one initial condition are prescribed, respectively, for the value function and the population density. In this paper, we show that uniqueness of solutions to the MFGS can be guaranteed if, among all four possible terminal and initial conditions, either only two terminals or only two initial conditions are given. In both cases, Hölder stability estimates are proven. This means that the accuracies of the solutions are estimated in terms of the given data. Moreover, these estimates readily imply uniqueness of corresponding problems for the MFGS. The main mathematical apparatus to establish those results is two new Carleman estimates, which may find application in other contexts associated with coupled parabolic PDEs. [ABSTRACT FROM AUTHOR]

CON-sup, normal fetal amniotic fluid sEVs; ANH-sup, ANH amniotic fluid sEVs; CON-cell, normal fetal amniotic fluid cells; ANH-cell, ANH amniotic fluid cells. gl To further explore the special expression pattern in sEVs of ANH, we compared the proteins and mRNAs in sEVs between ANH and normal samples, respectively. Dear Editor, Antenatal hydronephrosis (ANH) is the most common congenital anomaly of the urinary tract. In this study, we extracted small extracellular vesicles riched samples (sEVs) from supernatant amniotic fluid (AF), identified and verified the high expressed Moesin as an effective biomarker for ANH diagnosis. We identified 116 differential expression proteins (Figure 3A, B; Tables S3) and 836 differential expression mRNAs (Figure 3E, F, TableS4) between ANH amniotic fluid sEVs (ANH-sup) and normal fetal amniotic fluid sEVs (CON-sup). [Extracted from the article]

Background: Tympanic membrane perforation (TMP) is a common disease in otology, and few acellular techniques have been reported for repairing this condition. Decellularized extracellular matrix (ECM) scaffolds have been used in organ reconstruction. Objective: This study on tissue engineering aimed to develop a tympanic membrane (TM) scaffold prepared using detergent immersion and bone marrow mesenchymal stem cells (BMSCs) as repair materials to reconstruct the TM. Results: General structure was observed that the decellularized TM scaffold with BMSCs retained the original intact anatomical ECM structure, with no cell residue, as observed using scanning electron microscopy (SEM), and exhibited low immunogenicity. Therefore, we seeded the decellularized TM scaffold with BMSCs for recellularization. Histology and eosin staining, SEM and immunofluorescence in vivo showed that the recellularized TM patch had a natural ultrastructure and was suitable for the migration and proliferation of BMSCs. The auditory brainstem response (ABR) evaluated after recellularized TM patch repair was slightly higher than that of the normal TM, but the difference was not significant. Conclusion: The synthetic ECM scaffold provides temporary physical support for the three‐dimensional growth of cells during the tissue developmental stage. The scaffold stimulates cells to secrete their own ECM required for tissue regeneration. The recellularized TM patch shows potential as a natural, ultrastructure biological material for TM reconstruction. [ABSTRACT FROM AUTHOR]

Background: Hypopharynx reconstruction after hypopharyngectomy is still a great challenge. Perfusion decellularization is for extracellular matrix (ECM) scaffolding and had been used in organ reconstruction. Our study aimed to prepare an acellular, natural, three‐dimensional biological hypopharynx with vascular pedicle scaffold as the substitute materials to reconstruct hypopharynx. Result: Scanning electron microscope and histology staining showed that the decellularized hypopharynx with vascular pedicle scaffold retained intact native anatomical ECM structure. Myoblasts were observed on the recellularized scaffolds with bone marrow mesenchymal stem cells induced by 5‐azacytidine implanted in the rabbit greater omentum by immunohistochemical analysis. Conclusion: The decellularized hypopharynx with vascular pedicle scaffold prepared by detergent perfusion in our study has a potential to be an alternative material to pharynx reconstruction. [ABSTRACT FROM AUTHOR]

Gradients of conductivity and major ions in the coastal zone of the eastern Georgian Bay of Lake Huron appear to limit the spatial distribution of invasive dreissenid mussels. Rivers flowing into Georgian Bay from the Canadian Shield have relatively low conductivity compared to the main body of Lake Huron, which creates a gradient of solutes near the river mouths. Field observations show a strong positive correlation between conductivity and calcium concentration. Thus, we use conductivity to infer the calcium concentrations required for the successful growth of dreissenid mussels. Most dreissenid mussels were observed in regions where specific conductivities were greater than 140 μS/cm. Field observations were used to examine how the calcium poor river water mixes within the coastal zone, resulting in solute gradients that determine mussel distribution. When river flows are low in late summer, there is only a weak solute gradient across the coastal zone, implying an intrusion of open bay waters into the shallow embayments, that favor the growth of dreissenid mussels. In contrast, during spring when river flows are as much as 10 times higher, there is a strong solute gradient that extends further into the lake, and the low calcium appears to limit the growth of dreissenid mussels. Thus, the seasonal character of solute gradients helps describe the spatial distribution of dreissenid mussels and explains the localized absence of a species that is otherwise prevalent in much of the Laurentian Great Lakes. Key Points: Conductivity gradients across the coastal zone of eastern Georgian Bay of Lake Huron limits the dreissenid mussel distributionA circulation reminiscent of a partially mixed estuary in the fragmented archipelago influences the chemical and biological distributionsInvasive mussels are nearly absent in waters with low calcium and are only prevalent in regions of high calcium [ABSTRACT FROM AUTHOR]

The standard lattice Boltzmann method, which employs certain regular lattices coupled with discrete velocities as the computational grid, is limited in its flexibility to simulate flows in irregular geometries. To simulate large‐scale complex flows, we present a cell‐centered finite volume lattice Boltzmann method for incompressible flows on three‐dimensional (3D) unstructured grids and its corresponding parallel algorithm. The advective fluxes are calculated by the low‐diffusion Roe scheme, and the gradients of the particle distribution functions are computed with a least squares method. The presented scheme is validated by three benchmark flows: (a) a 3D Poiseuille flow, (b) cubic cavity flows with Reynolds numbers Re = 100 and 400, and (c) flows past a sphere with Re = 50, 100, 150, 200, and 250. Some parallel performance results are presented to show the scalability of the method, which reveal that the proposed parallel algorithm has considerable scalability and that the parallel efficiency is higher than 87% on 3840 processor cores. It can be seen that the presented parallel solver has significant potential for the accurate simulation of flows in complex 3D geometries. [ABSTRACT FROM AUTHOR]

The mixing and stratification present under ice‐covered lakes during winter can potentially influence the oxygen concentrations in the subsequent spring. During winter, plankton rely on updrafts caused by convection to remain in the photic zone and perform primary production. Thus, there is a crucial link in winter between under‐ice light levels, circulation, and dissolved oxygen (DO) production. Detailed observations of temperature, oxygen, and incoming solar radiation over three winters between 2015 and 2017 suggested that plankton abundance and DO concentrations were maximal near the end of the winter before the ice melted when there was increased under‐ice light and convection. DO was supersaturated by the end of the severe winter of 2015 when the ice cover duration was the longest. In comparison, DO increased but was not saturated in the warmer winters of 2016 and 2017. The spring overturn started when the water column became isothermal and continued until when the mean water column temperature first exceeded 4°C, at which time, hypolimnetic DO depletion started and continued until the fall overturn. The concentration of DO when the water column becomes stratified in spring, along with the timing of the end of spring overturn, are both important initial conditions for summer DO concentrations. [ABSTRACT FROM AUTHOR]

Based on a posteriori error estimator with hierarchical bases, an adaptive weak Galerkin finite element method (WGFEM) is proposed for the elliptic problem with mixed boundary conditions. For the posteriori error estimator, we are only required to solve a linear algebraic system with diagonal entries corresponding to the degree of freedoms, which significantly reduces the computational cost. The upper and lower bounds of the error estimator are shown to addresses the reliability and efficiency of the adaptive approach. Numerical simulations are provided to demonstrate the effectiveness and robustness of the proposed method. [ABSTRACT FROM AUTHOR]

Objectives: Hypoxic cancer cells have been shown to be more resistant to radiation therapy than normoxic cells. Hence, this study investigated whether ultrasound (US)‐induced rupture of oxygen‐carrying microbubbles (MBs) would enhance the response of breast cancer metastases to radiation. Methods: Nude mice (n = 15) received stereotactic injections of brain‐seeking MDA‐MB‐231 breast cancer cells into the right hemisphere. Animals were randomly assigned into 1 of 5 treatment groups: no intervention, 10 Gy radiation using a small‐animal radiation research platform, nitrogen‐carrying MBs combined with US‐mediated MB rupture immediately before 10 Gy radiation, oxygen‐carrying MBs immediately before 10 Gy radiation, and oxygen‐carrying MBs with US‐mediated MB rupture immediately before 10 Gy radiation. Tumor progression was monitored with 3‐dimensional US, and overall survival was noted. Results: All groups except those treated with oxygen‐carrying MB rupture and radiation had continued rapid tumor growth after treatment. Tumors treated with radiation alone showed a mean increase in volume ± SD of 337% ± 214% during the week after treatment. Tumors treated with oxygen‐carrying MBs and radiation without MB rupture showed an increase in volume of 383% ± 226%. Tumors treated with radiation immediately after rupture of oxygen‐carrying MBs showed an increase in volume of only 41% ± 1% (P = 0.045), and this group also showed a 1 week increase in survival time. Conclusions: Adding US‐ruptured oxygen‐carrying MBs to radiation therapy appears to delay tumor progression and improve survival in a murine model of metastatic breast cancer. [ABSTRACT FROM AUTHOR]

Objectives: To assess the performance of molecular lymphosonography with dual‐targeted microbubbles in detecting and quantifying the metastatic involvement in sentinel lymph nodes (SLNs) using a swine melanoma model. Methods: Targeted microbubbles were labeled with P‐selectin and αVβ3‐integrin antibodies. Control microbubbles were labeled with immunoglobulin G antibodies. First lymphosonography with Sonazoid (GE Healthcare, Oslo, Norway) was used to identify SLNs. Then dual‐targeted and control microbubbles were injected intravenously to detect and quantify metastatic disease in the SLNs. Distant non‐SLNs were imaged as benign controls. All evaluated lymph nodes (LNs) were surgically removed, and metastatic involvement was characterized by a histopathologic analysis. Two radiologists blinded to histopathologic results assessed the baseline B‐mode images of LNs, and the results were compared to the histologic reference standard. The mean intensities of targeted and control microbubbles within the examined LNs were measured and compared to the LN histologic results. Results: Thirty‐five SLNs and 34 non‐SLNs from 13 Sinclair swine were included in this study. Twenty‐one SLNs (62%) were malignant, whereas 100% of non‐SLNs were benign. The sensitivity of B‐mode imaging for metastatic LN diagnosis for both readers was relatively high (90% and 71%), but the specificity was very poor (50% and 58%). The sensitivity and specificity of molecular lymphosonography for metastatic LN detection were 91% and 67%, respectively. The mean intensities from dual‐targeted microbubbles correlated well with the degree of metastatic LN involvement (r = 0.6; P < 0.001). Conclusions: Molecular lymphosonography can increase the specificity of metastatic LN detection and provide a measure to quantify the degree of metastatic involvement. [ABSTRACT FROM AUTHOR]

Objectives: To investigate 3‐dimensional subharmonic aided pressure estimation (SHAPE) for measuring intraplaque pressure and the pressure gradient across the plaque cap as novel biomarkers for potentially predicting plaque vulnerability. Methods: Twenty‐seven rabbits received a high‐cholesterol diet for 2 weeks before a balloon catheter injury to denude the endothelium of the aorta, followed by 8 to 10 weeks of the high‐cholesterol diet to create arteriosclerotic plaques. SHAPE imagings of the resulting plaques were performed 12, 16, and 20 weeks after injury using a LOGIQ 9 scanner with a 4D10L probe (GE Healthcare, Milwaukee, WI) before and during an infusion of Definity (Lantheus Medical Imaging, North Billerica, MA) and Sonazoid (GE Healthcare, Oslo, Norway). The ratios of the maximum subharmonic magnitudes at baseline and during the infusion were correlated with the intraplaque pressure and pressure gradient across the plaque cap obtained from direct measurements. Results: Ten rabbits died prematurely after the balloon injury procedure or due to toxicity from the high‐cholesterol diet, whereas 2 rabbits were excluded for other conditions. Five rabbits were scanned in the 12‐, 16‐, and 20‐week groups, respectively. Even after 20 weeks, the plaques that developed were very small (mean ± SD, 0.9 ± 0.4 × 0.14 ± 0.05 cm). Definity performed better than Sonazoid in this application but still only achieved a moderate correlation with pressure across the plaque cap (Definity, r = –0.40; Sonazoid, r = 0.22) and intraplaque pressure (Definity, r = –0.19; Sonazoid, r = –0.11). Conclusions: Initial findings from plaque pressure estimation using 3‐dimensional SHAPE technique showed only moderate correlations with reference standards, but that may be have been due to weaknesses in the animal model studied. [ABSTRACT FROM AUTHOR]

A new fast numerical scheme is proposed for solving time-dependent coupled Burgers' equations. The idea of operator splitting is used to decompose the original problem into nonlinear pure convection subproblems and diffusion subproblems at each time step. Using Taylor's expansion, the nonlinearity in convection subproblems is explicitly treated by resolving a linear convection system with artificial inflow boundary conditions that can be independently solved. A multistep technique is proposed to rescue the possible instability caused by the explicit treatment of the convection system. Meanwhile, the diffusion subproblems are always self-adjoint and coercive at each time step, and they can be efficiently solved by some existing preconditioned iterative solvers like the preconditioned conjugate galerkin method, and so forth. With the help of finite element discretization, all the major stiffness matrices remain invariant during the time marching process, which makes the present approach extremely fast for the time-dependent nonlinear problems. Finally, several numerical examples are performed to verify the stability, convergence and performance of the new method. [ABSTRACT FROM AUTHOR]

Hsp104 is a yeast member of the Hsp100 family which functions as a molecular chaperone to disaggregate misfolded polypeptides. To understand the mechanism by which the Hsp104 N-terminal domain (NTD) interacts with its peptide substrates, crystal structures of the Hsp104 NTDs from Saccharomyces cerevisiae (ScHsp104NTD) and Candida albicans (CaHsp104NTD) have been determined at high resolution. The structures of ScHsp104NTD and CaHsp104NTD reveal that the yeast Hsp104 NTD may utilize a conserved putative peptide-binding groove to interact with misfolded polypeptides. In the crystal structures ScHsp104NTD forms a homodimer, while CaHsp104NTD exists as a monomer. The consecutive residues Gln105, Gln106 and Lys107, and Lys141 around the putative peptide-binding groove mediate the monomer-monomer interactions within the ScHsp104NTD homodimer. Dimer formation by ScHsp104NTD suggests that the Hsp104 NTD may specifically interact with polyQ regions of prion-prone proteins. The data may reveal the mechanism by which Hsp104 NTD functions to suppress and/or dissolve prions. [ABSTRACT FROM AUTHOR]

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins. [ABSTRACT FROM AUTHOR]

Mitochondrial preproteins are transported through the translocase of the outer membrane (TOM) complex. Tim50 and Tim23 then transfer preproteins with N-terminal targeting presequences through the intermembrane space (IMS) across the inner membrane. The crystal structure of the IMS domain of Tim50 [Tim50(164-361)] has previously been determined to 1.83 Å resolution. Here, the crystal structure of Tim50(164-361) at 2.67 Å resolution that was crystallized using a different condition is reported. Compared with the previously determined Tim50(164-361) structure, significant conformational changes occur within the protruding β-hairpin of Tim50 and the nearby helix A2. These findings indicate that the IMS domain of Tim50 exhibits significant structural plasticity within the putative presequence-binding groove, which may play important roles in the function of Tim50 as a receptor protein in the TIM complex that interacts with the presequence and multiple other proteins. More interestingly, the crystal packing indicates that helix A1 from the neighboring monomer docks into the putative presequence-binding groove of Tim50(164-361), which may mimic the scenario of Tim50 and the presequence complex. Tim50 may recognize and bind the presequence helix by utilizing the inner side of the protruding β-hairpin through hydrophobic interactions. Therefore, the protruding β-hairpin of Tim50 may play critical roles in receiving the presequence and recruiting Tim23 for subsequent protein translocations. [ABSTRACT FROM AUTHOR]

The recently determined C. elegans P-glycoprotein (Pgp) structure revealed significant deviations compared to the original mouse Pgp structure, which suggested possible misinterpretations in the latter model. To address this concern, we generated an experimental electron density map from single-wavelength anomalous dispersion phasing of an original mouse Pgp dataset to 3.8 Å resolution. The map exhibited significantly more detail compared to the original MAD map and revealed several regions of the structure that required de novo model building. The improved drug-free structure was refined to 3.8 Å resolution with a 9.4 and 8.1% decrease in Rwork and Rfree, respectively, ( Rwork = 21.2%, Rfree = 26.6%) and a significant improvement in protein geometry. The improved mouse Pgp model contains ∼95% of residues in the favorable Ramachandran region compared to only 57% for the original model. The registry of six transmembrane helices was corrected, revealing amino acid residues involved in drug binding that were previously unrecognized. Registry shifts (rotations and translations) for three transmembrane (TM)4 and TM5 and the addition of three N-terminal residues were necessary, and were validated with new mercury labeling and anomalous Fourier density. The corrected position of TM4, which forms the frame of a portal for drug entry, had backbone atoms shifted >6 Å from their original positions. The drug translocation pathway of mouse Pgp is 96% identical to human Pgp and is enriched in aromatic residues that likely play a collective role in allowing a high degree of polyspecific substrate recognition. [ABSTRACT FROM AUTHOR]

Mitochondrial precursors are transported through the translocase of the outer membrane (TOM) complex. Tom70/Tom71 is a major surface receptor of the TOM complex for mitochondrial precursors and facilitates Hsp70/Hsp90-escorted precursor translocation into the mitochondrion. Previous structural studies of Tom71 have revealed that it contains an N-terminal and a C-terminal domain and that the two domains may remain in an open conformation when binding to Hsp70/Hsp90. In a newly obtained crystal form of a complex of Tom71 and the Hsp70 C-terminus, the N-terminal domain was found to have rotated about 12° towards the C-terminal domain compared with the previous determined crystal structure of Tom71 in the open conformation. This newly solved structure is defined as the `intermediate conformation'. The domain rearrangements in Tom71 significantly change the surface hydrophobicity and the volume of the precursor-binding pocket. This work suggests that Tom70/Tom71-family members may exhibit structural plasticity from the intermediate conformation to the fully open conformation when complexed with Hsp70/Hsp90. This structural plasticity enables the precursor receptors to accommodate different precursor substrates for mitochondrial translocation. [ABSTRACT FROM AUTHOR]

Tail-anchored (TA) proteins contain a single transmembrane domain (TMD) at the C-terminus. The post-translational insertion of TA proteins into the ER membrane requires the cooperation of the Golgi ER-trafficking (GET) complex, which contains Get1, Get2 and Get3. Get3 is a cytosolic ATPase which can recognize and bind the TMD of the TA proteins. Get1 and Get2 are ER transmembrane proteins which can recruit and form a complex with TA-bound Get3. The GET complex carries out an energy-dependent process that facilitates the insertion of the TA-protein TMD into the ER membrane. In order to investigate the mechanism by which the GET complex functions to promote protein insertion into the ER membrane, yeast Get3 has been crystallized. The crystals diffracted to 2.7 Å resolution using a synchrotron X-ray source. The crystals belonged to space group P21212, with unit-cell parameters a = 220.26, b = 112.95, c = 48.27 Å. There is one Get3 dimer in the asymmetric unit, which corresponds to a solvent content of approximately 65%. [ABSTRACT FROM AUTHOR]

The endoplasmic reticulum (ER) unfolded protein response (UPR) is comprised of several intracellular signaling pathways that alleviate ER stress. The ER-localized transmembrane kinase PERK is one of three major ER stress transducers. Oligomerization of PERK's N-terminal ER luminal domain by ER stress promotes PERK trans-autophosphorylation of the C-terminal cytoplasmic kinase domain at multiple residues including Thr980 on the kinase activation loop. Activated PERK phosphorylates Ser51 of the α-subunit of translation initiation factor 2 (eIF2α), which inhibits initiation of protein synthesis and reduces the load of unfolded proteins entering the ER. The crystal structure of PERK's kinase domain has been determined to 2.8 Å resolution. The structure resembles the back-to-back dimer observed in the related eIF2α kinase PKR. Phosphorylation of Thr980 stabilizes both the activation loop and helix αG in the C-terminal lobe, preparing the latter for eIF2α binding. The structure suggests conservation in the mode of activation of eIF2α kinases and is consistent with a `line-up' model for PERK activation triggered by oligomerization of its luminal domain.

The mechanism by which Hsp40 functions as a molecular chaperone, recognizing and binding non-native polypeptides, is not understood. To investigate the mechanism, the yeast type I Hsp40 protein Ydj1 C-terminal peptide-binding fragment has been crystallized complexed with its peptide substrate. The crystals diffract to 2.70 A using a synchrotron X-ray source and belong to space group P3(2)21 or P3(1)21, with unit-cell parameters a = b = 55.21, c = 161.87 A, alpha = beta = 90, gamma = 120 degrees. There is one Ydj1 peptide-binding fragment and one peptide substrate in the asymmetric unit, which corresponds to a solvent content of approximately 42%. Structure determination by MAD methods is under way.

Escherichia coli Hsp100 ClpB has been identified recently as playing critical roles in multi-chaperone systems. ClpB binds and disaggregates denatured polypeptides by employing ATP hydrolysis and allows other molecular chaperones such as Hsp70 DnaK and Hsp40 DnaJ to refold the non-native polypeptides. ClpB contains two nucleotide-binding domains (NBD1 and NBD2) in its primary sequence. Walker A and Walker B motifs exist in both nucleotide-binding domains. Therefore, ClpB belongs to the large ATPase family known as ATPase associated with various cellular activities (AAA). The mechanisms by which NBD1 and NBD2 function to support the ClpB molecular-chaperone activity are currently unknown. To investigate how NBD2 participates in ClpB function to disaggregate denatured proteins, ClpB NBD2 has been cloned and crystallized. The ClpB NBD2 crystals diffract X-rays to 2.5 A using synchrotron X-ray sources. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 99.57, b = 149.34, c = 164.69 A.