Formation of self‐assembly nanotemplates in vitro by native SslA protein and its truncation analysis

Abstract S‐layer proteins are an issue of arising interest due to their ability to form periodical self‐assembly nanopore structures. In this work we analyze the self‐assembly potential of the recently characterized SslA S‐layer protein of Sporosarcina ureae and of truncated SslA derivatives. The SslA protein with an estimated molecular weight of 116 kDa is shown to self‐assemble in vitro into the periodic lattices with parameters identical to those of native S‐layers formed on the surface of bacterial cells. Recombinant SslA proteins with truncation of N‐, C‐, or both N‐ and C‐terminal parts were successfully overexpressed in E. coli and showed an aggregation behavior in vitro. A HisXXXHis motif in the central protein part is likely to contribute to self‐assembly through the coordination of adjacent SslA monomers by binding the procurable divalent metal ions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)