Author(s):
Mariutti, Ricardo B. [UNESP] ; Hernández-González, Jorge E. [UNESP] ; Nascimento, Andrey F.Z. ; de Morais, Mariana A.B. ; Murakami, Mario T. ; Carareto, Claudia M.A. [UNESP] ; Arni, Raghuvir K. [UNESP]
Date: 2020
Persistent ID: http://hdl.handle.net/11449/200200
Origin: Oasisbr
Subject(s): Arginine repressor; Corynebacterium pseudotuberculosis; Crystal structure; Free energy calculations; MD simulations; Arginine repressor; Arginine repressor; Corynebacterium pseudotuberculosis; Corynebacterium pseudotuberculosis; Crystal structure; Crystal structure; Free energy calculations; Free energy calculations; MD simulations; MD simulations
Description
Made available in DSpace on 2020-12-12T02:00:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
The arginine repressor (ArgR) regulates the expression of genes involved in arginine biosynthesis. Upon attaining a threshold concentration of arginine in the cytoplasm, the trimeric C-terminal domain of ArgR binds three arginines in a shallow surface cleft and subsequently hexamerizes forming a dimer of trimers containing six Arg co-repressor molecules which are buried at the subunit interfaces. The N-terminal domains of this complex bind to the DNA promoter thereby interrupting the transcription of the genes related to Arg biosynthesis. The crystal structures of the wild type and mutant Pro115Gln ArgR from Corynebacterium pseudotuberculosis determined at 1.7 Å demonstrate that a single amino acid substitution switches co-repressor specificity from Tyr to Arg. Molecular dynamics simulations indicate that the first step, i.e., the binding of the co-repressor, occurs in the trimeric state and that Pro115Gln ArgR preferentially binds Arg. It was also shown that, in Pro115 ArgR hexamers, the concomitant binding of sodium ions shifts selectivity to Tyr. Structural data combined with phylogenetic analyses of ArgR from C. pseudotuberculosis suggest that substitutions in the binding pocket at position 115 may alter its specificity for amino acids and that the length of the protein interdomain linker can provide further functional flexibility. These results support the existence of alternative ArgR regulatory mechanisms in this pathogenic bacterium.
Multiuser Center for Biomolecular Innovation IBILCE/UNESP
Department of Physics IBILCE/UNESP
Brazilian Synchrotron Light Laboratory (LNLS) Brazilian Center for Research in Energy and Materials (CNPEM)
Laboratory of Molecular Evolution IBILCE/UNESP
Multiuser Center for Biomolecular Innovation IBILCE/UNESP
Department of Physics IBILCE/UNESP
Laboratory of Molecular Evolution IBILCE/UNESP
FAPESP: 2015/13765-0
FAPESP: 2015/18868-2
FAPESP: 2016/19995-0
FAPESP: 2016/24587-9
FAPESP: 2018/07977-3
FAPESP: 2018/10736-8
