Structural implication of mutans of the pyridoxal kinase from Plasmodium falciparum.

Author(s)

Thales Kronenberger

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2014-02-13

Examining board members

Carsten Wrenger; Jorge Iulek; Gustavo Henrique Goulart Trossini

• Advisor: Carsten Wrenger

Abstract

Vitamin B9 metabolism is a known drug-target for malaria. Vitamin B6 was validated as essential for the parasite. We analysed biochemically and structurally the plasmodial dimeric pyridoxal kinase. PfPdxKs allowed us to determine the localisation of the active site as well the interface between the two monomers and to identify the involved residues. Molecular dynamics shows that the PdxKs dimerization is important for the active sites stability, which was confirmed by the decrease of activity in mutants related to this region. Gel filtration revealed equilibrium of monomer-dimer conformation and therefore the interface mutations decrease in activity might not be directly related to the dimerization processes, but rather to the active site organisation. The active site region shows a serine involved in keeping the pyridoxals conformation during catalyses and the identified lid region covering the ATP binding site is responsible for preventing auto-hydrolysis. Substitution of the respective amino acid to alanine resulted in enzyme inactivation. In silico analysis of the PfPdxK spacer region identified nucleic acid binding sides, however RNA binding experiments failed so far and the possibility of protein-RNA binding remains for elucidation. (AU)

• FAPESP's process: 11/13706-3 - Implications from pyridoxine kinase of Plasmodium falciparum and study if its spacer regions
• Grantee: Thales Kronenberger
• Support Opportunities: Scholarships in Brazil - Master