Abstract
In the whole genomic sequences of green sulfur bacterium Chlorobium tepidum revealed by The Institute for Genomic research (TIGR), no high homology gene coding for ferredoxin-NADP+ reductases (FNR) from oxygenic photosynthetic organisms was found. We purified a protein from this bacterium which supports NAD(P)+ reduction by reduced Fd and determined its N-terminal amino acid sequence. The protein exists as a dimer under physiological conditions, and its amino acid sequence deduced from TIGR database shows high similarity to NADPH-thioredoxin reductases (TR) found in various organisms, indicating that our purified enzyme represents a new FNR family. On BLAST search, several genes with high similarity to this FNR were found. However, these proteins have no conserved di-cysteine motif found in bona fide TRs.
Bacillus subtilis has two genes coding TR like proteins with high similarity scores. We are trying to purify FNR active proteins from B. subtilis.
