X-RAY STRUCTURE SOLUTION OF AMARYLLIS LECTIN BY MOLECULAR REPLACEMENTWITH ONLY 4-PERCENT OF THE TOTAL DIFFRACTING MATTER

Citation
L. Chantalat et al., X-RAY STRUCTURE SOLUTION OF AMARYLLIS LECTIN BY MOLECULAR REPLACEMENTWITH ONLY 4-PERCENT OF THE TOTAL DIFFRACTING MATTER, Acta crystallographica. Section D, Biological crystallography, 52, 1996, pp. 1146-1152
Citations number
20
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
1146 - 1152
Database
ISI
SICI code
0907-4449(1996)52:<1146:XSSOAL>2.0.ZU;2-1
Abstract
It is often the case that analogous proteins from different species cr ystallize in a different form. These structures can usually be easily solved by the molecular-replacement (MR) technique, as the protein fol ding is very often conserved. However, the results from MR become more uncertain as the proportion of diffracting matter decreases as a resu lt of multimericity and/or absence of some of the atoms in the model. In this paper results are presented on the structure solution of amary llis lectin (109 residues per monomer) containing two protein molecule s in the asymmetric unit. The structure was solved by MR using the C a lpha coordinates of one monomer from snowdrop lectin which has 85% ami no-acid sequence identity to amaryllis lectin. This represents only 6% of the non-H atoms of the protein molecule to be used for structure d etermination and it is a major improvement on previous reports. Furthe r calculations were carried out in order to establish the minimum numb er of atoms which could be included in the model before a clear soluti on to the MR problem was revealed, This study showed that the structur e of amaryllis lectin could still have been solved easily with 3.85% o f the model, which even in the most favourable cases, will probably co nstitute a minimum for molecular-replacement structure solution.