Solano R M, Langer I, Perret J, Vertongen P, Juarranz M G, Robberecht P, Waelbroeck M
Laboratoire de Chimie Biologique et de la Nutrition, Faculté de Médecine, Université Libre de Bruxelles, 808 route de Lennik, Building G/E, CP 611, B-1070 Brussels, Belgium.
J Biol Chem. 2001 Jan 12;276(2):1084-8. doi: 10.1074/jbc.M007696200.
We mutated the vasoactive intestinal peptide (VIP) Asp(3) residue and two VPAC(1) receptor second transmembrane helix basic residues (Arg(188) and Lys(195)). VIP had a lower affinity for R188Q, R188L, K195Q, and K195I VPAC(1) receptors than for VPAC(1) receptors. [Asn(3)] VIP and [Gln(3)] VIP had lower affinities than VIP for VPAC(1) receptors but higher affinities for the mutant receptors; the two basic amino acids facilitated the introduction of the negatively charged aspartate inside the transmembrane domain. The resulting interaction was necessary for receptor activation. 1/[Asn(3)] VIP and [Gln(3)] VIP were partial agonists at VPAC(1) receptors; 2/VIP did not fully activate the K195Q, K195I, R188Q, and R188L VPAC(1) receptors; a VIP analogue ([Arg(16)] VIP) was more efficient than VIP at the four mutated receptors; and [Asn(3)] VIP and [Gln(3)] VIP were more efficient than VIP at the R188Q and R188L VPAC(1) receptors; 3/the [Asp(3)] negative charge did not contribute to the recognition of the VIP(1) antagonist, [AcHis(1),D-Phe(2),Lys(15),Arg(16),Leu(27)] VIP ()/growth hormone releasing factor (8-27). This is the first demonstration that, to activate the VPAC(1) receptor, the Asp(3) side chain of VIP must penetrate within the transmembrane domain, in close proximity to two highly conserved basic amino acids from transmembrane 2.
我们对血管活性肠肽（VIP）的天冬氨酸（Asp）3位残基以及血管活性肠肽1型受体（VPAC(1)受体）第二个跨膜螺旋的两个碱性残基（精氨酸（Arg）188和赖氨酸（Lys）195）进行了突变。与VPAC(1)受体相比，VIP对R188Q、R188L、K195Q和K195I型VPAC(1)受体的亲和力较低。[天冬酰胺（Asn）3]VIP和[谷氨酰胺（Gln）3]VIP对VPAC(1)受体的亲和力低于VIP，但对突变受体的亲和力更高；这两个碱性氨基酸有助于带负电荷天冬氨酸进入跨膜结构域。由此产生的相互作用是受体激活所必需的。1/[Asn(3)]VIP和[Gln(3)]VIP是VPAC(1)受体的部分激动剂；2/VIP不能完全激活K195Q、K195I、R188Q和R188L型VPAC(1)受体；一种VIP类似物（[Arg(16)]VIP）在四种突变受体上比VIP更有效；[Asn(3)]VIP和[Gln(3)]VIP在R188Q和R188L型VPAC(1)受体上比VIP更有效；3/[Asp(3)]的负电荷对VIP(1)拮抗剂[乙酰组氨酸（AcHis）1，D-苯丙氨酸（D-Phe）2，Lys(15)，Arg(16)，亮氨酸（Leu）27]VIP/生长激素释放因子（8-27）的识别没有贡献。这是首次证明，为激活VPAC(1)受体，VIP的Asp(3)侧链必须穿透跨膜结构域，靠近跨膜2区的两个高度保守的碱性氨基酸。
