title: Biochemical and Structural Insights into the Aminotransferase CrmG in Caerulomycin Biosynthesis.
abstract: Caerulomycin A (CRM A 1) belongs to a family of natural products containing a 2,2'-bipyridyl ring core structure and is currently under development as a potent novel immunosuppressive agent. Herein, we report the functional characterization, kinetic analysis, substrate specificity, and structure insights of an aminotransferase CrmG in 1 biosynthesis. The aminotransferase CrmG was confirmed to catalyze a key transamination reaction to convert an aldehyde group to an amino group in the 1 biosynthetic pathway, preferring l-glutamate and l-glutamine as the amino donor substrates. The crystal structures of CrmG in complex with the cofactor 5'-pyridoxal phosphate (PLP) or 5'-pyridoxamine phosphate (PMP) or the acceptor substrate were determined to adopt a canonical fold-type I of PLP-dependent enzymes with a unique small additional domain. The structure guided site-directed mutagenesis identified key amino acid residues for substrate binding and catalytic activities, thus providing insights into the transamination mechanism of CrmG.
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Yiguang
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, China.
authors.forename: Jinxin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China , Qingdao 266003, China.
authors.forename: Xiangui
authors.initials: X
authors.lastname: Mei
authors.affiliation: Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, China.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Feng
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Guangtao
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China , Qingdao 266003, China.
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , 164 West Xingang Road, Guangzhou 510301, China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Zhang
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D000637:Transaminases / Q000737:chemistry / Q000378:metabolism*
chemical_list: C043637:cerulomycin; D015082:2,2'-Dipyridyl; D000637:Transaminases