Characterization and expression in Escherichi coli of Streptococcus pneumoniae FtsH.
- Author:
Heesoo KIM
1
;
Jae Jung LEE
Author Information
1. Department of Microbiology, College of Medicine, and Section of Genetic Engineering, The Medical Institute, Dongguk University, Kyongju, Kyongbuk, 780-350, South Korea. hskim@dongguk.ac.kr
- Publication Type:Original Article
- MeSH:
Amino Acid Sequence;
Blotting, Western;
Clone Cells;
Escherichia coli;
Gram-Positive Bacteria;
Hot Temperature;
Membranes;
Shock;
Streptococcus pneumoniae*;
Streptococcus*
- From:Journal of the Korean Society for Microbiology
2000;35(2):109-115
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
FtsH is a membrane-bound, ATP-dependent metalloprotease that is involved in a variety of cellular functions including the regulation of responses to heat and stress shock. Previously, we had cloned and sequenced pneumococcal ftsH gene whose deduced amino acid sequence was very similar to those of several gram-positive bacteria and Escherichia coli, except for the N-terminal domain that was responsible for membrane anchoring. In order to better understand the role of Streptococcus pneumoniae FtsH, we expressed pneumococcal ftsH gene in Escherichia coli. When it was expressed from a strong promoter, Ptac, a considerable amount of the recombinant FtsH was produced, although the prolonged induction resulted in not only accumulation of breakdown products but also ceasing of the further growth of E. coli host. This indicated that the expression of the exogenous ftsH gene was tightly regulated since the excessive FtsH appeared detrimental to bacterial cells. In Western blotting, the pneumococcal FtsH protein, whether native or recombinant, was reactive to anti-E. coli FtsH serum. The observation that FtsH proteins were well conserved throughout the bacterial kingdom and its expression level was fine-tuned suggests an important role for this protein in the stress adaptation which may be related to infecting process by pneumococci.
