Proteomic Topology

Science's STKE  31 May 2005:
Vol. 2005, Issue 286, pp. tw210
DOI: 10.1126/stke.2862005tw210

The global characterizations of protein composition, either of organisms or organelles, depends on analytical techniques optimized for soluble proteins, which comprise about 70% of the coding capacity of a genome. The remaining 30% have proven more difficult to analyze as a group. Daley et al. have used topological markers [alkaline phosphatase for the periplasm and green fluorescent protein (GFP) for the cytoplasm] to establish the inside-outside orientations of the C termini of almost all of the 700 inner membrane proteins in Escherichia coli. Combining these experimental determinations with prediction algorithms based on sequence yields a much improved database of how many times each of the polypeptides crosses the membrane and of where the N and C termini are located.

D. O. Daley, M. Rapp, E. Granseth, K. Melén, D. Drew, G. von Heijne, Global topology analysis of the Escherichia coli inner membrane proteome. Science 308, 1321-1323 (2005). [Abstract] [Full Text]