A single P115Q mutation modulates specificity in the Corynebacterium pseudotuberculosis arginine repressor

Author(s)

Mariutti, Ricardo B. ^[1] ; Hernandez-Gonzalez, Jorge E. ^[2] ; Nascimento, Andrey F. Z. ^[3] ; de Morais, Mariana A. B. ^[3] ; Murakami, Mario T. ^[3] ; Carareto, Claudia M. A. ^[4] ; Arni, Raghuvir K. ^{[2, 1]}

Affiliation

^[1] UNESP, Multiuser Ctr Biomol Innovat, IBILCE, Sao Jose Do Rio Preto, SP - Brazil

^[2] UNESP, Dept Phys, IBILCE, Sao Jose Do Rio Preto, SP - Brazil

^[3] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, Campinas, SP - Brazil

^[4] UNESP, IBILCE, Lab Mol Evolut, Sao Jose Do Rio Preto, SP - Brazil

• Document type: Journal article
• Source: BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS; v. 1864, n. 7 JUL 2020.
• Web of Science Citations: 0

Abstract

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 angstrom 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. (AU)

• FAPESP's process: 18/07977-3 - Structural biology, mechanisms and inhibitory strategies of proteins involved in the pathogenic dissemination.
• Grantee: Ricardo Barros Mariutti
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/13765-0 - Structural Studies and Characterization of Proteins by X-ray Crystallography and Nuclear Magnetic Resonance. Structural investigations and biophysics of molecular mechanisms of functional proteins.
• Grantee: Raghuvir Krishnaswamy Arni
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/19995-0 - Analysis of structural and functional diversity of GH43 enzymes from Xanthomonas axonopodis pv. citri: biological implications and potential biotechnological applications
• Grantee: Mariana Abrahão Bueno de Morais
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/18868-2 - Multi-user equipment acquisition for molecular and structural biology
• Grantee: Raghuvir Krishnaswamy Arni
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/10736-8 - Protein exfoliative D (ETD) of Staphylococcus aureus: inactivation / activation by synthetic peptides and characterization of complexes
• Grantee: Carolina Gismene
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 16/24587-9 - In silico identification of novel competitive and alosteric inhibitors of falcipains 2 and 3
• Grantee: Jorge Enrique Hernández González
• Support Opportunities: Scholarships in Brazil - Doctorate