Article info Vol. 6  No. 3   pp.  60 ~ 66
Title Aeromonas hydrophila cytosolic 5’-methylthioadenosine/S-adenosylhomocysteine nucleosidase MtaN-2: crystallization and X-ray crystallographic analysis
Authors Jinli Chen1,2, Fei Shang1,2, Lulu Wang1,3, Wei Liu1,2, Yuanyuan Chen1,2, Jing Lan1,2, Liming Jin1,2, Nam-Chul Ha4, Chunshan Quan1,2* and Yongbin Xu1,2*
Institutions 1Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China, 2Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China, 3School of Life Science and Biotechnology, Dalian University of Technology, No 2 Linggong Road, Dalian 116024, Liaoning, China, 4Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea *Correspondence: yongbinxu@dlnu.edu.cn, mikyeken@dlnu.edu.cn
Abstract 5’-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) plays a critical role in diverse pathways in bacterial cells such as biological methylation, polyamine biosynthesis, methionine recycling, and bacterial quorum sensing. It has been known that MtaN catalyzes the hydrolysis of N-ribosidic bond of adenosine-based substrates such as S-adenosyl-Lhomocysteine (SAH), S-methyl-5’-thioadenosine (MTA) and 5’-deoxyadenosine (5’-DOA). In Aeromonas hydrophila, there are two MtnN subfamily proteins: MtaN-1, a periplasmic protein with an N-terminal signal peptide; and MtaN-2, a cytosolic protein. In this study, MtaN-2 from A. hydrophila was successfully expressed and purified using Ni-NTA affinity, Q anionexchange, and gel-filtration chromatography. We first crystallized apo MtaN-2 but it diffracted to a low resolution of 5.1 Å. New crystals suitable for diffraction were obtained by adding 2 mM adenosine, a substrate analog of MtaN-2 during purification process and the crystals diffracted to the resolution of 2.0 Å. The crystals belong to the trigonal space group P31 or P32, with unit-cell parameters of a = b = 74.94 Å and c = 185.21 Å. The asymmetric unit contains four complexes of MtaN-2 with hydrolysis products of adenosine.