Download MendeleyStructural Insights into Substrate Specificity of Cystathionine gamma-Synthase from Corynebacterium glutamicum
Sagong, H.-Y., Kim, K.-J.(2017) J Agric Food Chem 65: 6002-6008
- PubMed: 28675039
- DOI: https://doi.org/10.1021/acs.jafc.7b02391
- Primary Citation of Related Structures:
5X5H - PubMed Abstract:
Cystathionine γ-synthase (MetB) condenses O-acetyl-l-homoserine (OAHS) or O-succinyl-l-homoserine (OSHS) with cysteine to produce cystathionine. To investigate the molecular mechanisms and substrate specificity of MetB from Corynebacterium glutamicum (CgMetB), we determined its crystal structure at 1.5 Å resolution. The pyridoxal phosphate cofactor is covalently bound to Lys204 via a Schiff base linkage in the deep cavity. Superposition with the structure of MetB from Nicotiana tabacum in complex with its inhibitor dl-(E)-2-amino-5-phosphono-3-pentenoic acid revealed that Thr347 from the β10-β11 connecting loop, located at the entrance of the active site, is speculated to be a main contributor for stabilization of the acetyl group of OAHS. Moreover, on the basis of structural comparison of CgMetB with EcMetB utilizing OSHS as a main substrate, we propose that the conformation of the β10-β11 connecting loops determines the size and shape of the acetyl- or succinyl-group binding site and ultimately determines the substrate specificity of MetBs toward OAHS or OSHS.
Organizational Affiliation:
KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University , Daehak-ro 80, Buk-ku, Daegu 702-701, Korea.
