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ヨコヤマ ケン
YOKOYAMA KEN
横山 謙 所属 京都産業大学 生命科学部 先端生命科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2006/01 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Leu(309) plays a critical role in the encapsulation of substrate protein into the internal cavity of GroEL |
| 執筆形態 | その他 |
| 掲載誌名 | JOURNAL OF BIOLOGICAL CHEMISTRY |
| 出版社・発行元 | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC |
| 巻・号・頁 | 281(2),pp.962-967 |
| 著者・共著者 | A Koike-Takeshita,T Shimamura,K Yokoyama,M Yoshida,H Taguchi |
| 概要 | In the crystal structure of the native GroEL center dot GroES center dot substrate protein complex from Thermus thermophilus, one GroEL subunit makes contact with two GroES subunits. One contact is through the H-I helices, and the other is through a novel GXXLE region. The side chain of Leu, in the GXXLE region, forms a hydrophobic cluster with residues of the H helix (Shimamura, T., Koike-Takeshita, A., Yokoyama, K., Masui, R., Murai, N., Yoshida, M., Taguchi, H., and Iwata, S. (2004) Structure (Camb.) 12, 1471-1480). Here, we investigated the functional role of Leu in the GXXLE region, using Escherichia coli GroEL. The results are as follows: (i) cross-linking between introduced cysteines confirmed that the GXXLE region in the E. coli GroEL center dot GroES complex is also in contact with GroES; (ii) when Leu was replaced by Lys (GroEL(L309K)) or other charged residues, chaperone activity was largely lost; (iii) the GroEL(L309K)center dot substrate complex failed to bind GroES to produce a stable GroEL(L309K)center dot GroES center dot substrate complex, whereas free GroEL( L309K) bound GroES normally; (iv) the GroEL(L309K)center dot GroES center dot substrate complex was stabilized with BeFx, but the substrate protein in the complex was readily digested by protease, indicating that it was not properly encapsulated into the internal cavity of the complex. Thus, conformational communication between the two GroES contact sites, the H helix and the GXXLE region (through Leu(309)), appears to play a critical role in encapsulation of the substrate. |
| DOI | 10.1074/jbc.M506298200 |
| ISSN | 0021-9258 |
| PMID | 16239229 |