Cyano2Dbase updated: linkage of 234 protein spots to corresponding genes through N-terminal microsequencing.

The cyanobacterium Synechocystis sp. strain PCC6803 is an interesting model organism for preoteome study because it is a photosynthetic procaryote and its genomic sequence has already been determined at our institute. We thus initiated characterization of this organism from a proteomic viewpoint by exploiting two-dimensional (2-D) gel electrophoresis coupled with N-terminal protein sequencing. In a previous study, we linked 130 protein spots on two dimensional gels with the genes that encoded them. As an extension of the previous study, the number of protein spots linked to their corresponding genes was increased to 227 in this study by separately analyzing cyanobacterial proteins in four different fractions (soluble, insoluble, thylakoid membrane, and secretory protein fractions). The resultant updated 2-D protein-gene linkage database, named Cyano2Dbase, will serve as an indispensable tool in future cyanobacterial proteomic studies. From the data compiled in the Cyano2Dbase, we can extract many items of information concerning translation, posttranslational processing including characteristics of cyanobacterial signal sequences and modification of cyanobacterial proteins. The Cyano2Dbase is available to the public through the World Wide Web (http://www.kazusa.or.jp/tech/sazuka/cyano/pr oteome.html).