AN X-RAY-ANALYSIS OF NATIVE MONOCLINIC LYSOZYME - A CASE-STUDY ON THERELIABILITY OF REFINED PROTEIN STRUCTURES AND A COMPARISON WITH THE LOW-HUMIDITY FORM IN RELATION TO MOBILITY AND ENZYME ACTION

Citation
Hg. Nagendra et al., AN X-RAY-ANALYSIS OF NATIVE MONOCLINIC LYSOZYME - A CASE-STUDY ON THERELIABILITY OF REFINED PROTEIN STRUCTURES AND A COMPARISON WITH THE LOW-HUMIDITY FORM IN RELATION TO MOBILITY AND ENZYME ACTION, Acta crystallographica. Section D, Biological crystallography, 52, 1996, pp. 1067-1074
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Crystallography,"Biochemical Research Methods",Biology
ISSN journal
0907-4449
Volume
52
Year of publication
1996
Part
6
Pages
1067 - 1074
Database
ISI
SICI code
0907-4449(1996)52:<1067:AXONML>2.0.ZU;2-Z
Abstract
The atomic models of native monoclinic lysozyme obtained by refinement at Bangalore and elsewhere [Young, Dewan, Nave & Tilton (1993). J. Ap pl. Cryst. 26, 309-319] differed significantly in the flexible regions of the protein molecule. The two models were reconciled starting from regions where they were in reasonable agreement to produce an improve d model which yielded an R value of 0.169 for 12 816 observed reflecti ons in the 10-2 Angstrom resolution range. The reconciled model was co mpared with the structure of the 88% relative humidity form obtained t hrough a water-mediated transformation [Madhusudan, Kodandapani & Vija yan (1993). Acta Cryst. D49, 234-245]. Parts of the flexible regions o f the molecule register significant movements during the transformatio n. The changes resulting from the transformation from the native to th e low-humidity forms are pronounced in many of the side chains in the active-site region, thus indicating the relationship between hydration , mobility and enzyme action. The fact that the overall changes in mol ecular geometry resulting from water-mediated transformation are simil ar to those which occur during enzyme action, further emphasizes this relationship.