Three-dimensional Structure of a New Enzyme, O-Phosphoserine Sulfhydrylase, involved in l-Cysteine Biosynthesis by a Hyperthermophilic Archaeon, Aeropyrum pernix K1, at 2.0A ResolutionOda, Y., Mino, K., Ishikawa, K., Ataka, M.
(2005) J Mol Biol 351: 334-344
- PubMed: 16005886
- DOI: 10.1016/j.jmb.2005.05.064
- Primary Citation of Related Structures:
- PubMed Abstract:
O-Phosphoserine sulfhydrylase is a new enzyme found in a hyperthermophilic archaeon, Aeropyrum pernix K1. This enzyme catalyzes a novel cysteine synthetic reaction from O-phospho-l-serine and sulfide. The crystal structure of the enzyme was determine ...
O-Phosphoserine sulfhydrylase is a new enzyme found in a hyperthermophilic archaeon, Aeropyrum pernix K1. This enzyme catalyzes a novel cysteine synthetic reaction from O-phospho-l-serine and sulfide. The crystal structure of the enzyme was determined at 2.0A resolution using the method of multi-wavelength anomalous dispersion. A monomer consists of three domains, including an N-terminal domain with a new alpha/beta fold. The topology folds of the middle and C-terminal domains were similar to those of the O-acetylserine sulfhydrylase-A from Salmonella typhimurium and the cystathionine beta-synthase from human. The cofactor, pyridoxal 5'-phosphate, is bound in a cleft between the middle and C-terminal domains through a covalent linkage to Lys127. Based on the structure determined, O-phospho-l-serine could be rationally modeled into the active site of the enzyme. An enzyme-substrate complex model and a mutation experiment revealed that Arg297, unique to hyperthermophilic archaea, is one of the most crucial residues for O-phosphoserine sulfhydrylation activity. There are more hydrophobic areas and less electric charges at the dimer interface, compared to the S.typhimurium O-acetylserine sulfhydrylase.
Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST, Kansai), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.