title: Human carbamoyl phosphate synthetase I (CPSI): insights on the structural role of the unknown function domains.
abstract: Carbamoyl phosphate synthetase (CPS) is an ancient protein. In mammals it intervenes in the urea cycle. This enzyme is organized into six domains, three of which have no established role in the mammalian enzyme. Taking advantage of the high degree of conservation between the human and the Escherichia coli homologue a comparative study was carried out in order to infer about the biological role of these less characterized domains. We show that among the residues involved in the maintenance of quaternary structure of the E. coli enzyme, several are highly conserved between human and bacterial enzyme and match the homologous positions of the "unknown function" domains in human enzyme, suggesting they are involved in the structural stability of the human enzyme as they are in bacteria.
authors.affiliation: IPATIMUP - Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. monicaslm@hotmail.com
authors.forename: Monica
authors.initials: M
authors.lastname: Lopes-Marques
authors.forename: Gilberto
authors.initials: G
authors.lastname: Igrejas
authors.forename: António
authors.initials: A
authors.lastname: Amorim
authors.forename: Luisa
authors.initials: L
authors.lastname: Azevedo
mesh_terms: D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000737:chemistry* / Q000235:genetics; D017124:Conserved Sequence; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D008956:Models, Chemical; D017434:Protein Structure, Tertiary; D056806:Urea Cycle Disorders, Inborn / Q000201:enzymology / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D002222:Carbamoyl-Phosphate Synthase (Ammonia)