Structural and functional analysis of SilP, a P1-type ATPase from the sil family involved in bacterial silver resistance.

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Silver (Ag+) is a heavy metal commonly used within burns wards as a lining in bandages and as an additive within creams to help prevent infections, owing to heavy metals being highly toxic to bacterial cells. Due to the use of silver as a preventative treatment, certain strains of bacteria have developed resistance to silver. Analysis of the resistant bacteria identified the presence of a plasmid containing nine genes encoding for proteins believed to be involved in silver exportation, they were labelled sil proteins.My current research focuses on one of these proteins, SilP, this is a P1B-type ATPase that exports Ag+ from the cytoplasm of the bacterial into the periplasm of the cell membrane at the expense of ATP. SilP follows the Post-Albers catalytic cycle, wherein there are four main conformational states of the protein during exportation of Ag+. The main aim of my research looks at obtaining an overall structure of SilP, using both crystallography, Cryo-EM and neutron scattering. In addition to the overall structure is the aim of getting a structure at each of the four stages of the catalytic cycle, this would give an indication of metal movement within the protein and how it exports Ag+. Although the main aim is the structural determination of SilP, the other aims are to carry out functional assays looking at ATP usage and rate of Ag+ exportation as well as other biophysical aspects of SilP.