Reference: Ammon HL, et al. (1988) Preliminary crystal structure of Acinetobacter glutaminasificans glutaminase-asparaginase. J Biol Chem 263(1):150-6

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Abstract


The preliminary structure of a glutaminase-asparaginase from Acinetobacter glutaminasificans is reported. The structure was determined at 3.0-A resolution with a combination of phase information from multiple isomorphous replacement at 4-5-A resolution and phase improvement and extension by two density modification techniques. The electron density map was fitted by a polypeptide chain that was initially polyalanine. This was subsequently replaced by a polypeptide with an amino acid sequence in agreement with the sizes and shapes of the side chain electron densities. The crystallographic R factor is 0.300 following restrained least squares refinement with data to 2.9-A resolution. The A. glutaminasificans glutaminase-asparaginase subunit folds into two domains: the aminoterminal domain contains a five-stranded beta sheet surrounded by five alpha helices, while the carboxyl-terminal domain contains three alpha helices and less regular structure. The connectivity is not fully determined at present, due in part to the lack of a complete amino acid sequence. The A. glutaminasificans glutaminase-asparaginase structure has been used successfully to determine the relative orientations of the molecules in crystals of Pseudomonas 7A glutaminase-asparaginase, in crystals of Vibrio succinogenes asparaginase, and in a new crystal form of Escherichia coli asparaginase (space group 1222, one subunit per asymmetric unit).

Reference Type
Comparative Study | Journal Article | Research Support, U.S. Gov't, Non-P.H.S. | Research Support, U.S. Gov't, P.H.S.
Authors
Ammon HL, Weber IT, Wlodawer A, Harrison RW, Gilliland GL, Murphy KC, Sjölin L, Roberts J