Lorena Ilcu

Abstract

Cytochromes c are a widespread and essential class of proteins found in almost every group of organisms from the kingdoms of prokaryotes, archaea and eukaryotes. They contain the cofactor heme covalently attached to the protein chain, and they consequently require dedicated maturation systems to carry out this posttranslational modification. For bacterial cytochrome c maturation, predominantly two distinct systems are utilized: system I, also known as the Ccm system (cytochrome c maturation) and system II, the Ccs system (cytochrome c synthesis). In contrast to the far more elaborate Ccm system, the Ccs system involves only four membrane-bound proteins: CcsA, CcsB, CcdA and CcsX. Among these, CcsA and CcsB form the actual cytochrome c synthase complex that catalyzes the covalent linkage of peptide and cofactor, while CcdA and CcsX fulfill a redox mediator function to retain the cysteine residues of the conserved heme-binding motifs in the peptide chain, CXXCH, in a reduced state. My aim is to obtain single crystals of a CcsBA complex in order to solve the first three-dimensional structure of such an enzyme by X-ray crystallography.

Methods

• Molecular biology techniques

• Membrane protein expression and purification

• Crystallization

• X-ray structure determination

• UV-VIS spectroscopy

Publications

Ilcu, L, Röther, W, Birke, J, Brausemann, A, Einsle, O & Jendrossek, D (2017) Structural and functional analysis of latex clearing protein (Lcp) provides insight into the enzymatic cleavage of rubber. Sci. Rep., 7, 6179.