1cr7
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1cr7" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cr7, resolution 2.60Å" /> '''PEANUT LECTIN-LACTOS...)
Next diff →
Revision as of 10:34, 20 November 2007
|
PEANUT LECTIN-LACTOSE COMPLEX MONOCLINIC FORM
Overview
The crystal structures of a monoclinic and a triclinic form of the peanut, lectin-lactose complex, grown at pH 4.6, have been determined. They, contain two and one crystallographically independent tetramers, respectively. The unusual "open" quaternary structure of the lectin, observed in the orthorhombic complex grown in neutral pH, is retained at, the acidic pH. The sugar molecule is bound to three of the eight subunits, in the monoclinic crystals, whereas the combining sites in four are empty., The lectin-sugar interactions are almost the same at neutral and acidic, pH. A comparison of the sugar-bound and free subunits indicates that the, geometry of the combining site is relatively unaffected by ligand binding., The combining site of the eighth subunit in the monoclinic crystals is, bound to a peptide stretch in a loop from a neighboring molecule. The same, interaction exists in two subunits of the triclinic crystals, whereas, density corresponding to sugar exists in the combining sites of the other, two subunits. Solution studies show that oligopeptides with sequences, corresponding to that in the loop bind to the lectin at acidic pH, but, only with reduced affinity at neutral pH. The reverse is the case with the, binding of lactose to the lectin. A comparison of the neutral and acidic, pH crystal structures indicates that the molecular packing in the latter, is directed to a substantial extent by the increased affinity of the, peptide loop to the combining site at acidic pH.
About this Structure
1CR7 is a Single protein structure of sequence from Arachis hypogaea with CA and MN as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structures of the peanut lectin-lactose complex at acidic pH: retention of unusual quaternary structure, empty and carbohydrate bound combining sites, molecular mimicry and crystal packing directed by interactions at the combining site., Ravishankar R, Thomas CJ, Suguna K, Surolia A, Vijayan M, Proteins. 2001 May 15;43(3):260-70. PMID:11288176
Page seeded by OCA on Tue Nov 20 12:41:47 2007
