title: Crystal structure of the protein L-isoaspartyl methyltransferase from Escherichia coli.
abstract: Among the known covalent damages that can occur spontaneously to proteins, the formation of isoaspartyl linkages through deamidation of asparagines and isomerization of aspartates may be one of the most rapid forms under conditions of physiological pH and temperature. The protein L-isoaspartyl methyltransferase (PIMT) is thought to recognize L-isoaspartyl residues and repair this kind of damaged proteins. Curiously, there is a potential functional difference between bacterial and mammalian PIMTs. Herein, we present the crystal structure of Escherichia coli PIMT (EcPIMT) at a resolution of 1.8 Å. The enzyme we investigated was able to remain bound to its product S-adenosylhomocysteine (SAH) during crystallization. Analysis indicates that the high affinity of EcPIMT for SAH might lead to the lower activity of the enzyme.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, People's Republic of China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Fang
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Xing
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Liwen
authors.initials: L
authors.lastname: Niu
authors.forename: Maikun
authors.initials: M
authors.lastname: Teng
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006639:Histidine / Q000235:genetics / Q000378:metabolism; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012435:S-Adenosylhomocysteine / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011994:Recombinant Proteins; D006639:Histidine; D012435:S-Adenosylhomocysteine; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase