9LDT image
Deposition Date 1991-11-26
Release Date 1993-10-31
Last Version Date 2024-10-16
Entry Detail
PDB ID:
9LDT
Title:
DESIGN AND SYNTHESIS OF NEW ENZYMES BASED ON THE LACTATE DEHYDROGENASE FRAMEWORK
Biological Source:
Source Organism:
Sus scrofa (Taxon ID: 9823)
Method Details:
Experimental Method:
Resolution:
2.00 Å
R-Value Observed:
0.23
Space Group:
P 21 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:LACTATE DEHYDROGENASE
Gene (Uniprot):LDHA
Chain IDs:A, B
Chain Length:332
Number of Molecules:2
Biological Source:Sus scrofa
Primary Citation
Design and synthesis of new enzymes based on the lactate dehydrogenase framework.
Philos.Trans.R.Soc.London,Ser.B 332 177 184 (1991)
PMID: 1678537

Abstact

Analysis of the mechanism and structure of lactate dehydrogenases is summarized in a map of the catalytic pathway. Chemical probes, single tryptophan residues inserted at specific sites and a crystal structure reveal slow movements of the protein framework that discriminate between closely related small substrates. Only small and correctly charged substrates allow the protein to engulf the substrate in an internal vacuole that is isolated from solvent protons, in which water is frozen and hydride transfer is rapid. The closed vacuole is very sensitive to the size and charge of the substrate and provides discrimination between small substrates that otherwise have too few functional groups to be distinguished at a solvated protein surface. This model was tested against its ability to successfully predict the design and synthesis of new enzymes such as L-hydroxyisocaproate dehydrogenase and fully active malate dehydrogenase. Solvent friction limits the rate of forming the vacuole and thus the maximum rate of catalysis.

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Primary Citation of related structures