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Publication Abstract from PubMed

A deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94, has a beta-agarase (MtAgaA) belonging to the glycoside hydrolase family (GH) 16. The optimal temperature of this bacterium for growth is 43-49 degrees C, and MtAgaA is stable at 60 degrees C, which is one of the most thermostable enzymes among GH16 beta-agarases. Here, we determined the catalytic domain structure of MtAgaA. MtAgaA consists of a beta-jelly roll fold, as observed in other GH16 enzymes. The structure of MtAgaA was most similar to two beta-agarases from Zobellia galactanivorans, ZgAgaA, and ZgAgaB. Although the catalytic cleft structure of MtAgaA was similar to ZgAgaA and ZgAgaB, residues at subsite -4 of MtAgaA were not conserved between them. Also, an alpha-helix, designated as alpha4', was uniquely located near the catalytic cleft of MtAgaA. A comparison of the structures of the three enzymes suggested that multiple factors, including increased numbers of arginine and proline residues, could contribute to the thermostability of MtAgaA.

Crystal structure of the catalytic domain of a GH16 beta-agarase from a deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94.,Takagi E, Hatada Y, Akita M, Ohta Y, Yokoi G, Miyazaki T, Nishikawa A, Tonozuka T Biosci Biotechnol Biochem. 2015 Apr;79(4):625-32. doi:, 10.1080/09168451.2014.988680. Epub 2014 Dec 6. PMID:25483365^[1]

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