6L0S

Crystal Structure of the O-Phosphoserine Sulfhydrylase from Aeropyrum pernix Complexed with L-Cysteine

Summary for 6L0S

• Entry DOI: 10.2210/pdb6l0s/pdb
• Descriptor: Protein CysO, (2R)-2-[(E)-[2-methyl-3-oxidanyl-5-(phosphonooxymethyl)pyridin-4-yl]methylideneamino]-3-sulfanyl-propanoic acid, (4S)-2-METHYL-2,4-PENTANEDIOL, ... (4 entities in total)
• Functional Keywords: cysteine biosynthesis, sulfhydrylase, transferase
• Biological source: Aeropyrum pernix K1
• Total number of polymer chains: 4
• Total formula weight: 169228.04

Authors

Nakabayashi, M.,Takeda, E.,Ishikawa, K.,Nakamura, T. (deposition date: 2019-09-26, release date: 2020-09-23, Last modification date: 2024-10-23)

Primary citation

Takeda, E.,Matsui, E.,Kiryu, T.,Nakagawa, T.,Nakabayashi, M.,Ishikawa, K.,Nakamura, T.
Identification of amino acid residues important for recognition of O-phospho-l-serine substrates by cysteine synthase.
J.Biosci.Bioeng., 131:483-490, 2021

PubMed Abstract: Pyridoxal-5'-phosphate-dependent cysteine synthases synthesize l-cysteine from their primary substrates, O-acetyl-l-serine (OAS) and O-phospho-l-serine (OPS), and their secondary substrate, sulfide. The mechanism by which cysteine synthases recognize OPS remains unclear; hence, we investigated the OPS recognition mechanism of the OPS sulfhydrylase obtained from Aeropyrum pernix K1 (ApOPSS) and the OAS sulfhydrylase-B obtained from Escherichia coli (EcOASS-B), using protein engineering methods. From the amino acid sequence alignment data, we found that some OPS sulfhydrylases (OPSSs) had a Tyr corresponding to the Phe225 and Phe141 residues in ApOPSS and EcOASS-B, respectively, and that the Tyr residue could facilitate OPS recognition. The enzymatic activity of the ApOPSS F225Y mutant toward OPS decreased compared with that of the wild-type; the k value decreased 2.3-fold during cysteine synthesis. X-ray crystallography results of the complex of ApOPSS F225Y and F225Y/R297A mutants bound to OPS and l-cysteine showed that k might have decreased because of the stronger interactions of the reaction product phosphate with Tyr225, Thr203, and Arg297, and that of the l-cysteine with Tyr225. The specific activity of the EcOASS-B F141Y mutant toward OPS increased by 50-fold compared with that of the wild-type. Thus, a Tyr within a cysteine synthase corresponding to the Phe225 in ApOPSS and Phe141 in EcOASS-B could act as a key residue for classifying an unknown cysteine synthase as an OPSS. The elucidation of the substrate recognition system of cysteine synthases would enable us to effectively classify cysteine synthases and develop pathogen-specific drug targets, as OPSS is absent in mammalian hosts.

PubMed: 33563496
DOI: 10.1016/j.jbiosc.2021.01.003

Experimental method

X-RAY DIFFRACTION (1.96 Å)