Skip Navigation


Journal of Biochemistry Advance Access originally published online on November 21, 2007
Journal of Biochemistry 2008 143(2):237-242; doi:10.1093/jb/mvm212
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
143/2/237    most recent
mvm212v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by Kim, Y.-T.
Right arrow Articles by Takahashi, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kim, Y.-T.
Right arrow Articles by Takahashi, K.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2007 The Japanese Biochemical Society.

The Effects of Mutations in the Carboxyl-Terminal Region on the Catalytic Activity of Escherichia coli Signal Peptidase I

Yong-Tae Kim1,2, Hisashi Yoshida1, Masaki Kojima3, Ryo Kurita1, Wataru Nishii2,3, Tomonari Muramatsu2, Hisashi Ito1, Sun Joo Park4,* and Kenji Takahashi3,{dagger}

1Department of Chemistry, Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Kanagawa 229-8558; 2RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045; 3School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392; and 4Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8539, Japan

*To whom correspondence should be addressed. Fax: +81 78 3825419, E-mail: parksj{at}med.kobe-u.ac.jp

{dagger}Correspondence may also be addressed. Fax: +81 49 2978168, E-mail: kenjitak{at}ls.toyaku.ac.jp

Received October 20, 2007; Accepted October 30, 2007


  Abstract

Escherichia coli signal peptidase I (SPase I) is a membrane-bound serine endopeptidase that catalyses the cleavage of signal peptides from the pre-forms of membrane or secretory proteins. Our previous studies using chemical modification and site-directed mutagenesis suggested that Trp300 and Arg77, Arg222, Arg315 and Arg318 are important for the proper and stable conformation of the active site of SPase I. Interestingly, many of these residues reside in the C-terminal region of the enzyme. As a continuation of these studies, we investigated in the present study the effects of mutations in the C-terminal region including amino acid residues at positions from 319 to 323 by deletions and site-directed mutagenesis. As a result, the deletion of the C-terminal His323 was shown to scarcely affect the enzyme activity of SPase I, whereas the deletion of Gly321-His323 or Ile319-His323 as well as the point mutation of Ile322 to alanine was shown to decrease significantly both the activity in vitro and in vivo without a big gross conformational change in the enzyme. These results suggest a significant contribution of Ile322 to the construction and maintenance of the proper and critical local conformation backing up the active site of SPase I.

Key Words: carboxyl-terminal residues, deletion, Escherichia coli, signal peptidase I, site-directed mutagenesis


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.