Zymomonas mobilis is unique among bacteria in its ability to produce high levels of ethanol (EtOH) during fermentation. Elevated EtOH concentration, like elevated temperature, is a microbial stress and a universal inducer of stress proteins. For Z. mobilis, exposure to high levels of EtOH represents a natural stress. By using a simple strategy which combines the genetic tools of Escherichia coli and Bacillus subtilis, we have cloned genes encoding two of the most abundant stress proteins in Z. mobilis, GroES and GroEL. Both genes were expressed at high levels in E. coli. Despite the unique environment (EtOH concentrations of above 10%) in which the translated products from these genes function in Z. mobilis, the amino-acid sequences encoded were remarkably similar to their homologues from bacteria which are not known to accumulate EtOH. Two small regions were observed, however, which appear more similar to Saccharomyces cerevisiae hsp60 (groEL homologue) than to E. coli or the concensus. These may be related to EtOH tolerance.

• PMID: 7926837
• DOI full text
• PubMed

Reference Type

Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, Non-P.H.S.

Authors

Barbosa MF, Yomano LP, Ingram LO

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