High-affinity insulin binding: insulin interacts with two receptor ligand binding sites.
High-affinity insulin binding: insulin interacts with two receptor ligand binding sites.
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DOI：
10.1021/bi801693h
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发表时间：
2008-12-02
期刊：
影响因子：
2.9
通讯作者：
Whittaker, Jonathan
中科院分区：
文献类型：
--
作者：
Whittaker, Linda;Hao, Caili;Fu, Wen;Whittaker, Jonathan
胰岛素与其受体的相互作用是复杂的。动力学和平衡结合的研究表明共存的高和低亲和力结合位点和/或负协同性。这些现象和高亲和力相互作用依赖于受体的二聚体结构。胰岛素类似物的结构-功能研究表明，胰岛素有两个受体结合位点，这意味着与受体的二价相互作用。对分泌型重组受体的丙氨酸扫描研究表明，受体α亚基的L1结构域和C-末端肽是一个配体结合位点的组成部分。功能研究表明，受体的第一和第二III型纤连蛋白重复序列含有第二配体结合位点。我们已经使用结构导向的丙氨酸扫描诱变，以确定在这些领域参与配体相互作用的决定因素。编码全受体丙氨酸突变体的cDNA在293细胞中瞬时表达，并测定所表达受体的结合特性。Lys 484、Leu 552、Asp 591、Ile 602、Lys 616、Asp 620和Pro621的丙氨酸突变使胰岛素亲和力降低2- 5倍。除Asp 620外，这些突变均未损害重组分泌型受体对胰岛素的亲和力，表明相互作用的干扰发生在突变位点，而不是对与分泌型受体结合位点相互作用的间接影响。因此，这些残基形成胰岛素受体的新配体结合位点的一部分。互补实验表明，胰岛素与两个受体结合位点反式相互作用，产生高亲和力的相互作用。
The interaction of insulin with its receptor is complex. Kinetic and equilibrium binding studies suggest co-existence of high and low affinity binding sites and/or negative cooperativity. These phenomena and high affinity interactions are dependent on the dimeric structure of the receptor. Structure-function studies of insulin analogs suggest insulin has two receptor binding sites, implying a bivalent interaction with the receptor. Alanine scanning studies of the secreted recombinant receptor implicate the L1 domain and a C-terminal peptide of the receptor α subunit as components of one ligand binding site. Functional studies suggest that the first and second Type III fibronectin repeats of the receptor contain a second ligand binding site. We have used structure directed alanine scanning mutagenesis to identify determinants in these domains involved in ligand interactions. cDNAs encoding alanine mutants of the holo-receptor were transiently expressed in 293 cells and the binding properties of the expressed receptor determined. Alanine mutations of Lys484, Leu552, Asp591, Ile602, Lys616, Asp620 and Pro621 compromised affinities for insulin 2- to 5- fold. With the exception of Asp620, none of these mutations compromised the affinity of the recombinant secreted receptor for insulin, indicating that the perturbation of the interaction is at the site of mutation and not an indirect effect on the interaction with the binding site of the secreted receptor. These residues thus form part of a novel ligand binding site of the insulin receptor. Complementation experiments demonstrate that insulin interacts in trans- with both receptor binding sites to generate high affinity interactions.
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影响因子：
2.9
作者：
HEDO, JA;HARRISON, LC;ROTH, J
通讯作者：
ROTH, J
DOI：
10.1098/rstb.1988.0058
发表时间：
1988-07-06
影响因子：
6.3
作者：
BAKER, EN;BLUNDELL, TL;VIJAYAN, NM
通讯作者：
VIJAYAN, NM
影响因子：
14.9
作者：
Kirsch, RD;Joly, E
通讯作者：
Joly, E
影响因子：
5.6
作者：
Huang, K;Xu, B;Weiss, MA
通讯作者：
Weiss, MA
影响因子：
3.5
作者：
Hoyne, PA;Cosgrove, LJ;Ward, CW
通讯作者：
Ward, CW