A mutational study of Cnu reveals attractive forces between Cnu and H-NS |
| |
Authors: | Sang Hoon Yun Sang Chun Ji Heung Jin Jeon Xun Wang Younghoon Lee Byong-Seok Choi Heon M. Lim |
| |
Affiliation: | Department of Biology, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764, Korea. |
| |
Abstract: | Cnu is a small 71-amino acid protein that complexes with H-NS and binds to a specific sequence in the replication origin of the E. coli chromosome. To understand the mechanism of interaction between Cnu and H-NS, we used bacterial genetics to select and analyze Cnu variants that cannot complex with H-NS. Out of 2,000 colonies, 40 Cnu variants were identified. Most variants (82.5%) had a single mutation, but a few variants (17.5%) had double amino acid changes. An in vitro assay was used to identify Cnu variants that were truly defective in H-NS binding. The changes in these defective variants occurred exclusively at charged amino acids (Asp, Glu, or Lys) on the surface of the protein. We propose that the attractive force that governs the Cnu-H-NS interaction is an ionic bond, unlike the hydrophobic interaction that is the major attractive force in most proteins. |
| |
Keywords: | Cnu DNA binding H-NS protein-protein interaction |
本文献已被 PubMed SpringerLink 等数据库收录! |
|