Crystal Structure and Functional Characterization of Acetylornithine Aminotransferase from Corynebacterium glutamicum

• Published in: Journal of agricultural and food chemistry Vol. 71; no. 22; pp. 8471 - 8478
• Main Authors: Ki, Dongwoo, Hong, Hwaseok, Kim, Il-kwon, Kim, Kyung-Jin
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.06.2023
• Subjects: Biotechnology and Biological Transformations; crystal structure; pyridoxal-5′-phosphate; l-arginine; Corynebacterium glutamicum; acetylornithine aminotransferase
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.3c00659

The amino acids l-arginine and l-ornithine are widely used in animal feed and as health supplements and pharmaceutical compounds. In arginine biosynthesis, acetylornithine aminotransferase (AcOAT) uses pyridoxal-5′-phosphate (PLP) as a cofactor for amino group transfer. Here, we determined the crystal structures of the apo and PLP complex forms of AcOAT from Corynebacterium glutamicum (CgAcOAT). Our structural observations revealed that CgAcOAT undergoes an order-to-disorder conformational change upon binding with PLP. Additionally, we observed that unlike other AcOATs, CgAcOAT exists as a tetramer. Subsequently, we identified the key residues involved in PLP and substrate binding based on structural analysis and site-directed mutagenesis. This study might provide structural insights on CgAcOAT, which can be utilized for the development of improved l-arginine production enzymes.