Structure of Escherichia coli AMP nucleosidase reveals similarity to nucleoside phosphorylases.
AMP nucleosidase (AMN) catalyzes the hydrolysis of AMP to form adenine and ribose 5-phosphate. The enzyme is found only in prokaryotes, where it plays a role in purine nucleoside salvage and intracellular AMP level regulation. Enzyme activity is stimulated by ATP and suppressed by phosphate. The structure of unliganded AMN was determined at 2.7 A resolution, and structures of the complexes with either formycin 5'-monophosphate or inorganic phosphate were determined at 2.6 A and 3.0 A resolution, respectively. AMN is a biological homohexamer, and each monomer is composed of two domains: a catalytic domain and a putative regulatory domain. The overall topology of the catalytic domain and some features of the substrate binding site resemble those of the nucleoside phosphorylases, demonstrating that AMN is a new member of the family. The structure of the regulatory domain consists of a long helix and a four-stranded sheet and has a novel topology.
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
Yang
Y
Zhang
Sarah E
SE
Cottet
Steven E
SE
Ealick
D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology; D005573:Formycins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000737:chemistry*; D010430:Pentosyltransferases / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D012265:Ribonucleotides / Q000737:chemistry*; D012267:Ribosemonophosphates / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
D005573:Formycins; D010710:Phosphates; D012265:Ribonucleotides; D012267:Ribosemonophosphates; C021683:formycin 5'-phosphate; C031626:ribose-5-phosphate; D010430:Pentosyltransferases; C067995:nucleoside phosphorylase; D009699:N-Glycosyl Hydrolases; C019699:AMP nucleosidase