oxidized Human Branched Chain Aminotransferase mutant C318Aoxidized Human Branched Chain Aminotransferase mutant C318A

Structural highlights

6prx is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 3.25Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

BCAT2_HUMAN Catalyzes the first reaction in the catabolism of the essential branched chain amino acids leucine, isoleucine, and valine. May also function as a transporter of branched chain alpha-keto acids.

Publication Abstract from PubMed

This study presents the crystal structure of a thiol variant of the human mitochondrial branched-chain aminotransferase protein. Human branched-chain aminotransferase (hBCAT) catalyzes the transamination of the branched-chain amino acids leucine, valine and isoleucine and alpha-ketoglutarate to their respective alpha-keto acids and glutamate. hBCAT activity is regulated by a CXXC center located approximately 10 A from the active site. This redox-active center facilitates recycling between the reduced and oxidized states, representing hBCAT in its active and inactive forms, respectively. Site-directed mutagenesis of the redox sensor (Cys315) results in a significant loss of activity, with no loss of activity reported on the mutation of the resolving cysteine (Cys318), which allows the reversible formation of a disulfide bond between Cys315 and Cys318. The crystal structure of the oxidized form of the C318A variant was used to better understand the contributions of the individual cysteines and their oxidation states. The structure reveals the modified CXXC center in a conformation similar to that in the oxidized wild type, supporting the notion that its regulatory mechanism depends on switching the Cys315 side chain between active and inactive conformations. Moreover, the structure reveals conformational differences in the N-terminal and inter-domain region that may correlate with the inactivated state of the CXXC center.

Crystal structure of an oxidized mutant of human mitochondrial branched-chain aminotransferase.,Herbert D, Gibbs S, Riddick A, Conway M, Dong M Acta Crystallogr F Struct Biol Commun. 2020 Jan 1;76(Pt 1):14-19. doi:, 10.1107/S2053230X19016480. Epub 2020 Jan 1. PMID:31929181[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Herbert D, Gibbs S, Riddick A, Conway M, Dong M. Crystal structure of an oxidized mutant of human mitochondrial branched-chain aminotransferase. Acta Crystallogr F Struct Biol Commun. 2020 Jan 1;76(Pt 1):14-19. doi:, 10.1107/S2053230X19016480. Epub 2020 Jan 1. PMID:31929181 doi:http://dx.doi.org/10.1107/S2053230X19016480

6prx, resolution 3.25Å

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