ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
It is often found in the crystallization of enzyme–inhibitor complexes that an inhibitor causes crystal packing which is different to that of native protein. This is the case for crystals of human non-pancreatic secreted phospholipase A2 (124 residues) containing six molecules in the asymmetric unit when the protein is complexed with a potential acylamino analogue of a phospholid. The hexameric structure was determined by molecular replacement using the structure of monomeric native protein as a probe. As an extension to the experiment, it was tested whether a backbone polypeptide composed of 17% of a known monomeric structure could find its correct position on a target molecule in molecular replacement. A probe model composed of the backbone atoms of the N-terminal 77 residues of lysine-, arginine-, ornithine-binding protein (LAO, a total of 238 residues) liganded with lysine correctly finds its position on LAO liganded with histidine which crystallizes as a monomer in the asymmetric unit. The results indicate that as little as 17% of total diffracting matter can be used in molecular replacement to solve crystal structures or to obtain phase information which can be combined with phases obtained by the isomorphous-replacement method.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444994010024
