鸟苷 5'-单磷酸形成四螺旋的无序单晶证据。

Disordered single crystal evidence for a quadruple helix formed by guanosine 5'-monophosphate.

作者信息

Lipanov A A, Quintana J, Dickerson R E

机构信息

Molecular Biology Institute, University of California, Los Angeles 90024.

出版信息

J Biomol Struct Dyn. 1990 Dec;8(3):483-9. doi: 10.1080/07391102.1990.10507824.

DOI:10.1080/07391102.1990.10507824

PMID:1966063

Abstract

The disodium salt of guanosine 5'-monophosphate (5'-GMP) has been crystallized earlier in an orthorhombic array. We have obtained a new crystal form of 5'-GMP at pH 8 which reveals a clear helical nature, with guanine bases stacked perpendicular to the helix axis. Although the X-ray pictures show partial disorder, they can be indexed on a hexagonal net with a = b = 28.6 A, c = 9.8 A, V = 6942 A3 (1A = 0.1 nm). The probable space group is P6(4), and past experience with ca. 600 A3 per base in oligonucleotide crystals suggests that the cell contains 12 GMP molecules. The crystal packing parameters and the intensity distribution agree with a model of three hydrogen-bonded guanine tetrads in the unit cell, stacked so as to build a quadruple helix similar to that proposed earlier from fiber studies (Zimmerman, S.B., J. Mol. Biol. 106, 663-672 (1976)).

摘要

鸟苷 5'-单磷酸（5'-GMP）二钠盐此前已在正交晶系中结晶。我们在 pH 8 条件下获得了 5'-GMP 的一种新晶型，其呈现出明显的螺旋结构，鸟嘌呤碱基垂直于螺旋轴堆积。尽管 X 射线照片显示存在部分无序，但它们可以在一个六方网中进行指标化，其中 a = b = 28.6 Å，c = 9.8 Å，V = 6942 Å³（1 Å = 0.1 nm）。可能的空间群是 P6(4)，根据寡核苷酸晶体中每个碱基约 600 Å³ 的以往经验表明，晶胞中含有 12 个 GMP 分子。晶体堆积参数和强度分布与晶胞中三个氢键连接的鸟嘌呤四联体模型相符，这些四联体堆叠在一起形成了一个类似于早期纤维研究中提出的四重螺旋结构（齐默尔曼，S.B.，《分子生物学杂志》106，663 - 672（1976））。