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Biophysical characterization of an essential protein complex for bacterial cell wall formation

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Mayara Mayele Miyachiro
Total Authors: 1
Document type: Doctoral Thesis
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Andréa Dessen; Juliana Helena Costa Smetana; Andre Luís Berteli Ambrosio; Ana Carolina de Mattos Zeri; Gustavo Fernando Mercaldi
Advisor: Andréa Dessen

Protein interactions play important biological roles for cells, as in the case of the biosynthesis of peptidoglycan (PG), the major component of the bacterial cell wall. The PG is involved in the determination of cell morphology and protection against osmotic stress, both in Gram-negative and Gram-positive bacteria. The synthesis of PG is a dynamic and highly complex process, which requires many steps mediated by different enzymes located in different compartments of the cell. The Mur (MurC to MurF) ligases are responsible for the catalysis of the synthesis of PG precursors in the cytoplasm, together with the MurG and MraY proteins, which are related to the synthesis of lipid I and lipid II respectively. These proteins are essential for bacterial survival and are found only in prokaryotic organisms, and are thus potential targets for the development of new antibiotics. Here we present the expression and purification of MraY from Streptococcus pneumoniae, an integral membrane protein, as well as its analysis of the interaction with MurF. There is vast evidence regarding the formation of complexes between these proteins; however, this work describes, for the first time, the direct interaction between the Mur ligases of Streptococcus pneumoniae, which form a mega-complex in solution. We also observed that the interaction between these proteins is strongly related to the presence of their oligomeric forms. Interestingly, we have found that S. pneumoniae MurG is able to self-associate and form different oligomeric species in solution. This fact represents a dynamic process, important for the assembly of a mega-complex within the cytoplasm, and could be representative of a spatial and temporal PG-regulatory mechanism (AU)

FAPESP's process: 13/02451-0 - Structural characterization of an essential protein complex in cell wall formation
Grantee:Mayara Mayele Miyachiro
Support Opportunities: Scholarships in Brazil - Doctorate (Direct)