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Enzyme catalysis prior to aromatic residues: Reverse engineering of a dephospho‐CoA kinase
- Source :
- Protein Sci
- Publication Year :
- 2021
- Publisher :
- Wiley, 2021.
-
Abstract
- The wide variety of protein structures and functions results from the diverse properties of the 20 canonical amino acids. The generally accepted hypothesis is that early protein evolution was associated with enrichment of a primordial alphabet, thereby enabling increased protein catalytic efficiencies and functional diversification. Aromatic amino acids were likely among the last additions to genetic code. The main objective of this study was to test whether enzyme catalysis can occur without the aromatic residues (aromatics) by studying the structure and function of dephospho-CoA kinase (DPCK) following aromatic residue depletion. We designed two variants of a putative DPCK from Aquifex aeolicus by substituting (i) Tyr, Phe and Trp or (ii) all aromatics (including His). Their structural characterization indicates that substituting the aromatics does not markedly alter their secondary structures but does significantly loosen their side chain packing and increase their sizes. Both variants still possess ATPase activity, although with 150-300 times lower efficiency in comparison with the wild-type phosphotransferase activity. The transfer of the phosphate group to the dephospho-CoA substrate becomes heavily uncoupled and only the His-containing variant is still able to perform the phosphotransferase reaction. These data support the hypothesis that proteins in the early stages of life could support catalytic activities, albeit with low efficiencies. An observed significant contraction upon ligand binding is likely important for appropriate organization of the active site. Formation of firm hydrophobic cores, which enable the assembly of stably structured active sites, is suggested to provide a selective advantage for adding the aromatic residues. This article is protected by copyright. All rights reserved.
- Subjects :
- Stereochemistry
Full‐Length Papers
Biochemistry
Catalysis
Protein Structure, Secondary
Enzyme catalysis
Phosphotransferase
03 medical and health sciences
chemistry.chemical_compound
Residue (chemistry)
Protein structure
Bacterial Proteins
Catalytic Domain
Aromatic amino acids
Molecular Biology
030304 developmental biology
chemistry.chemical_classification
0303 health sciences
Aquifex aeolicus
biology
030302 biochemistry & molecular biology
Active site
biology.organism_classification
Amino acid
Aquifex
Phosphotransferases (Alcohol Group Acceptor)
Amino Acid Substitution
chemistry
Mutagenesis, Site-Directed
biology.protein
Subjects
Details
- ISSN :
- 1469896X and 09618368
- Volume :
- 30
- Database :
- OpenAIRE
- Journal :
- Protein Science
- Accession number :
- edsair.doi.dedup.....5703c95dd965f5d6745c8bb4bfd2e4ed