8CQG image
Deposition Date 2023-03-06
Release Date 2023-06-21
Last Version Date 2024-11-13
Entry Detail
PDB ID:
8CQG
Keywords:
Title:
Crystal Structure of a Chimeric Alpha-Amylase from Pseudoalteromonas Haloplanktis
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.74 Å
R-Value Free:
0.20
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Alpha-amylase
Gene (Uniprot):amy
Mutations:A77V Q204L S226G T227A E228K N231T T232L G270_G271insA A272G G273S N274S V275I I276L D310N T311D D312W
Chain IDs:A
Chain Length:450
Number of Molecules:1
Biological Source:Pseudoalteromonas haloplanktis
Primary Citation
Computational design of the temperature optimum of an enzyme reaction.
Sci Adv 9 eadi0963 eadi0963 (2023)
PMID: 37379391 DOI: 10.1126/sciadv.adi0963

Abstact

Cold-adapted enzymes are characterized both by a higher catalytic activity at low temperatures and by having their temperature optimum down-shifted, compared to mesophilic orthologs. In several cases, the optimum does not coincide with the onset of protein melting but reflects some other type of inactivation. In the psychrophilic α-amylase from an Antarctic bacterium, the inactivation is thought to originate from a specific enzyme-substrate interaction that breaks around room temperature. Here, we report a computational redesign of this enzyme aimed at shifting its temperature optimum upward. A set of mutations designed to stabilize the enzyme-substrate interaction were predicted by computer simulations of the catalytic reaction at different temperatures. The predictions were verified by kinetic experiments and crystal structures of the redesigned α-amylase, showing that the temperature optimum is indeed markedly shifted upward and that the critical surface loop controlling the temperature dependence approaches the target conformation observed in a mesophilic ortholog.

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Primary Citation of related structures