LOW RESOLUTION STRUCTURE OF PARTIALLY TRYPSIN-DEGRADED POLYPEPTIDE ELONGATION-FACTOR, EF-TU, FROM ESCHERICHIA-COLI
LOW RESOLUTION STRUCTURE OF PARTIALLY TRYPSIN-DEGRADED POLYPEPTIDE ELONGATION-FACTOR, EF-TU, FROM ESCHERICHIA-COLI
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DOI：
10.1016/s0022-2836(77)80009-0
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发表时间：
1977-01-01
影响因子：
5.6
通讯作者：
LEBERMAN, R
中科院分区：
文献类型：
--
作者：
KABSCH, W;GAST, WH;LEBERMAN, R
The low resolution structure of a trypsin-modified form of EF-Tu from E. coli was determined by X-ray crystallographic methods. The crystals belong to space group P212121 with 2 molecules in the asymmetric unit. The phase determination was based on three isomorphous heavy-atom derivatives. The quality of the resulting electron density map at 6 .ANG. was sufficient to identify the molecules. The 2 molecules in the asymmetric unit are related by a non-crystallographic 2-fold rotation. A molecular model was derived by averaging the electron density of the 2 molecules at equivalent points. Its overall dimensions are 75 .ANG. .times. 50 .ANG. .times. 35 .ANG.. The molecule consists of a compact globular head of dimensions 45 .ANG. .times. 40 .ANG. .times. 40 .ANG. and a curled tail of diameter 25 .ANG. and length 55 .ANG.. There is a 2nd connection between head and tail, probably an .alpha.-helix, such that the molecule forms a ring. The large groove in the center could accommodate a RNA double helix. The head has a high .alpha.-helical content but the tail seems to be helix-free. A MW of 43,000 was derived from the electron density map indicating that no major part of the molecule is missing. Possible interactions between EF-Tu and tRNA are discussed.
