Critical Roles of Interactions among Switch I-preceding Residues and between Switch II and Its Neighboring α-Helix in Conformational Dynamics of the GTP-bound Ras Family Small GTPases

被引：13

作者：

Matsumoto, Kousuke ^{[1
]}

Shima, Fumi ^{[1
]}

Muraoka, Shin ^{[1
,4
]}

Araki, Mitsugu ^{[2
]}

Hu, Lizhi ^{[1
]}

Ijiri, Yuichi ^{[1
]}

Hirai, Rina ^{[1
]}

Liao, Jingling ^{[1
]}

Yoshioka, Takashi ^{[2
]}

Kumasaka, Takashi ^{[3
]}

Yamamoto, Masaki ^{[4
]}

Tamura, Atsuo ^{[2
]}

Kataoka, Tohru ^{[1
]}

机构：

[1] Kobe Univ, Grad Sch Med, Dept Biochem & Mol Biol, Div Mol Biol,Chuo Ku, Kobe, Hyogo 6500017, Japan

[2] Kobe Univ, Grad Sch Sci, Dept Chem, Nada Ku, Kobe, Hyogo 6578501, Japan

[3] Japan Synchrotron Radiat Res Inst JASRI, Sayo, Hyogo 6795198, Japan

[4] RIKEN SPring 8 Ctr, Mikazuki, Hyogo 6795148, Japan

来源：

JOURNAL OF BIOLOGICAL CHEMISTRY | 2011年 / 286卷 / 17期

关键词：

CRYSTAL-STRUCTURE; ACTIVATING PROTEIN; STRUCTURAL BASIS; BINDING; P21(RAS); STATE;

D O I：

10.1074/jbc.M110.204933

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

GTP-bound forms of Ras family small GTPases exhibit dynamic equilibrium between two interconverting conformations, "inactive" state 1 and "active" state 2. A great variation exists in their state distribution; H-Ras mainly adopts state 2, whereas M-Ras predominantly adopts state 1. Our previous studies based on comparison of crystal structures representing state 1 and state 2 revealed the importance of the hydrogen-bonding interactions of two flexible effector-interacting regions, switch I and switch II, with the gamma-phosphate of GTP in establishing state 2 conformation. However, failure to obtain both state structures from a single protein hampered further analysis of state transition mechanisms. Here, we succeed in solving two crystal structures corresponding to state 1 and state 2 from a single Ras polypeptide, M-RasD41E, carrying an H-Ras-type substitution in residue 41, immediately preceding switch I, in complex with guanosine 5'-(beta,gamma-imido)triphosphate. Comparison among the two structures and other state 1 and state 2 structures of H-Ras/M-Ras reveal two new structural features playing critical roles in state dynamics; interaction of residues 31/41 (H-Ras/M-Ras) with residues 29/39 and 30/40, which induces a conformational change of switch I favoring its interaction with the gamma-phosphate, and the hydrogen-bonding interaction of switch II with its neighboring alpha-helix, alpha 3-helix, which induces a conformational change of switch II favoring its interaction with the gamma-phosphate. The importance of the latter interaction is proved by mutational analyses of the residues involved in hydrogen bonding. These results define the two novel functional regions playing critical roles during state transition.

引用

页码：15403 / 15412

页数：10