Proteomic and genomic strategy for the study of the extremely acidophilic Acidithiobacillus ferrooxidans

摘要

The recent availability of an incomplete genomic sequence from At. ferrooxidans allowed us to continue and strengthen the demanding task of investigating the proteome and its functional implications in this extremophilic microorganism. The proteins of At. ferrooxidans were separated by two-dimensional polyacrylamide gel electrophoresis and their levels of synthesis and the microsequencing of their N-terminal end amino acids were determined. To link the 2D gel spots of interest with the genes that encode them, we studied the global changes in gene expression of At. ferrooxidans when the bacterium was confronted with changes in pH, oxidizible substrate, and during nutrient starvation. By comparing the amino acid sequences of the proteins whose synthesis was induced or repressed under the different conditions, with the available At. ferrooxidans genomic database, we found several putative genes whose expression may be related to iron or sulfur oxidation and to phosphate starvation. Analysis of the genome DNA sequences upstream and downstream of these genes showed us details of the possible structure of putative operons present in At ferrooxidans, such as the Pho regulon and others. It is expected that the DNA microarray technology, once available for At. ferrooxidans combined with the recently described method of introducing genes into this chemolithoautotroph will greatly help in understanding how these microorganisms interact and adapt to their biomining environment.