title: Crystal structure of the N-terminal domain of E. coli Lon protease.
abstract: We report here the first crystal structure of the N-terminal domain of an A-type Lon protease. Lon proteases are ubiquitous, multidomain, ATP-dependent enzymes with both highly specific and non-specific protein binding, unfolding, and degrading activities. We expressed and purified a stable, monomeric 119-amino acid N-terminal subdomain of the Escherichia coli A-type Lon protease and determined its crystal structure at 2.03 A (Protein Data Bank [PDB] code 2ANE). The structure was solved in two crystal forms, yielding 14 independent views. The domain exhibits a unique fold consisting primarily of three twisted beta-sheets and a single long alpha-helix. Analysis of recent PDB depositions identified a similar fold in BPP1347 (PDB code 1ZBO), a 203-amino acid protein of unknown function from Bordetella parapertussis, crystallized as part of a structural genomics effort. BPP1347 shares sequence homology with Lon N-domains and with a family of other independently expressed proteins of unknown functions. We postulate that, as is the case in Lon proteases, this structural domain represents a general protein and polypeptide interaction domain.
authors.affiliation: Macromolecular Crystallography Laboratory, National Cancer Institute, Building 536, Room 5, Frederick, MD 21702-1201, USA.
authors.forename: Mi
authors.initials: M
authors.lastname: Li
authors.forename: Fatima
authors.initials: F
authors.lastname: Rasulova
authors.forename: Edward E
authors.initials: EE
authors.lastname: Melnikov
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Rotanova
authors.forename: Alla
authors.initials: A
authors.lastname: Gustchina
authors.forename: Michael R
authors.initials: MR
authors.lastname: Maurizi
authors.forename: Alexander
authors.initials: A
authors.lastname: Wlodawer
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049070:Protease La / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D040681:Structural Homology, Protein
chemical_list: D029968:Escherichia coli Proteins; C483567:Lon protein, E coli; D049070:Protease La