NMR - PSEUDOENERGY APPROACH TO THE SOLUTION STRUCTURE OF ACYL CARRIER PROTEIN
NMR - PSEUDOENERGY APPROACH TO THE SOLUTION STRUCTURE OF ACYL CARRIER PROTEIN
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DOI：
10.1021/bi00389a010
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发表时间：
1987-07-28
期刊：
影响因子：
2.9
通讯作者：
FORMAN, JD
中科院分区：
文献类型：
--
作者：
HOLAK, TA;PRESTEGARD, JH;FORMAN, JD
以酰基载体蛋白的短氨基酸片段为测试用例，提出并探索了一种从二维核磁共振交叉弛豫数据中测定蛋白质结构的方法。该方法基于分子力学程序，并以伪能量项的形式纳入核磁共振距离约束，以准确反映核磁共振交叉弛豫数据的距离依赖精度。当它以不加区分的方式使用时，该方法倾向于在起始结构附近产生表示局部能量最小值的结构，而不是表示全局能量最小值的结构。然而，逐步包含能量项，从一个由主干距离约束重加权的函数开始，似乎可以简化势能面，使各种起始结构收敛到一个共同的主干结构成为可能。在酰基载体蛋白残基3 ~ 15的片段中，一个近乎完美的。-螺旋从一个线性链开始产生，一个。alpha。-螺旋链，或具有线性和-交替残基的链。-螺旋主干扭角。在残基26至36段的情况下，产生具有右手环的结构。
A method for protein structure determination from two-dimensional NMR cross-relaxation data is presented and explored by using short amino acid segments from acyl carrier protein as a test case. The method is based on a molecular mechanics program and incorporates NMR distance constraints in the form of a pseudoenergy term that accurately reflects the distance-dependent precision of NMR cross-relaxation data. When it is used in an indiscriminant fashion, the method has a tendency to produce structures representing local energy minima near starting structures, rather than structures representing a global energy minimum. However, stepwise inclusion of energy terms, beginning with a function heavily weighted by backbone distance constraints, appears to simplify the potential energy surface to a point where convergence to a common backbone structure from a variety of starting structures is possible. In the case of the segment from residues 3 to 15 in acyl carrier protein, a nearly perfect .alpha.-helix is produced starting with a linear chain, an .alpha.-helical chain, or a chain having residues with alternating linear and .alpha.-helica backbone torsional angles. In the case of the segment from residues 26 to 36 a structure having a right-handed loop is produced.