6TTL image
Entry Detail
PDB ID:
6TTL
Keywords:
Title:
crystal structure of [FeFe]-hydrogenase CbA5H (partial) from Clostridium beijerinckii in Hinact state
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2019-12-28
Release Date:
2020-12-09
Method Details:
Experimental Method:
Resolution:
2.90 Å
R-Value Free:
0.35
R-Value Work:
0.33
Space Group:
P 42 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:[FeFe]-hydrogenase
Chain IDs:A, B
Chain Length:674
Number of Molecules:2
Biological Source:Clostridium beijerinckii
Primary Citation
A safety cap protects hydrogenase from oxygen attack.
Nat Commun 12 756 756 (2021)
PMID: 33531463 DOI: 10.1038/s41467-020-20861-2

Abstact

[FeFe]-hydrogenases are efficient H2-catalysts, yet upon contact with dioxygen their catalytic cofactor (H-cluster) is irreversibly inactivated. Here, we combine X-ray crystallography, rational protein design, direct electrochemistry, and Fourier-transform infrared spectroscopy to describe a protein morphing mechanism that controls the reversible transition between the catalytic Hox-state and the inactive but oxygen-resistant Hinact-state in [FeFe]-hydrogenase CbA5H of Clostridium beijerinckii. The X-ray structure of air-exposed CbA5H reveals that a conserved cysteine residue in the local environment of the active site (H-cluster) directly coordinates the substrate-binding site, providing a safety cap that prevents O2-binding and consequently, cofactor degradation. This protection mechanism depends on three non-conserved amino acids situated approximately 13 Å away from the H-cluster, demonstrating that the 1st coordination sphere chemistry of the H-cluster can be remote-controlled by distant residues.

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Primary Citation of related structures