wARP: Improvement and extension of crystallographic phases by weighted averaging of multiple-refined dummy atomic models

被引:480
作者
Perrakis, A
Sixma, TK
Wilson, KS
Lamzin, VS
机构
[1] UNIV YORK, DEPT CHEM, PROT STRUCT GRP, YORK YO1 5DD, N YORKSHIRE, ENGLAND
[2] DESY, EUROPEAN MOL BIOL LAB, D-22603 HAMBURG, GERMANY
来源
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY | 1997年 / 53卷
关键词
D O I
10.1107/S0907444997005696
中图分类号
Q5 [生物化学];
学科分类号
071010 ; 081704 ;
摘要
wARP is a procedure that substantially improves crystallographic phases (and subsequently electron-density maps) as an additional step after density-modification methods such as solvent flattening and averaging. The initial phase set is used to create a number of dummy atom models which are subjected to least-squares of maximum-likelihood refinement and iterative model updating in an automated refinement procedure (ARP). Averaging of the phase sets calculated from the refined output models and weighting of structure factors by their similarity to an average vector results in a phase set that improves and extends the initial phases substantially. An important requirement is that the native data have a maximum resolution beyond similar to 2.4 Angstrom. The wARP procedure shortens the time-consuming step of model building in crystallographic structure determination and helps to prevent the introduction of errors.
引用
收藏
页码:448 / 455
页数:8
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