Sequence analysis of the third dnaK homolog gene in Synechococcus sp. PCC7942.

The nucleotide sequence of the third dnaK homolog gene from Synechococcus sp. PCC7942 has been determined. Deduced amino acid sequences of dnaK3 and of previously reported dnaK1 and dnaK2 were compared with Hsp70s from various species. Among the three DnaK homologs, DnaK2 shows close relationship to chloroplast proteins and DnaK3 also has some similarities to them. On the other hand, DnaK1 has few chloroplast-specific motifs and forms a deep branch of the prokaryotic cluster in the phylogenetic tree.