3t6e

Publication Abstract from PubMed

Newly determined crystal structures of the photosynthetic reaction centre (RC) from two substrains of the non-sulphur purple bacterium Blastochloris viridis strain DSM 133, together with analysis of their gene sequences, has revealed intra-species evolutionary changes over a time period of 14 years. Over one hundred point mutations were identified between these two substrains in the four genes encoding the protein subunits of the RC, of which about one fifth resulted in a total of 16 amino acid changes. The most interesting difference was in the M subunit where the change from leucine to glycine in the carotenoid binding pocket allowed dihydroneurosporene to adopt a more sterically favoured conformation and similar to the carotenoid conformation found in other related reaction centres. Our results together with a high rate of mutations in laboratory bacterial cultures described recently [Perfeito, Fernandes, Mota and Gordo (2007) Science 317, 813-815] suggest that bacteria evolve faster than has been generally recognised. The possibility that amino acid changes occur within protein sequences, without exhibiting any immediately observable phenotype, should be taken into account in studies that involve long-term continuous growth of pure bacterial cultures. The Blastochloris viridis RC is often studied with sophisticated biophysical techniques and changes such as those described here may well affect their outcome. In other words, there is a danger that laboratory-to-laboratory variation could well be due to different groups not realising that they are actually working with slightly different proteins. A way around this problem is suggested.

New Insights into the Structure of the Reaction Centre from Blastochloris viridis: Evolution in the Laboratory.,Roszak AW, Moulisova V, Reksodipuro AD, Gardiner AT, Fujii R, Hashimoto H, Isaacs NW, Cogdell RJ Biochem J. 2011 Nov 4. PMID:22054235^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.