2akq
From Proteopedia
The structure of bovine B-lactoglobulin A in crystals grown at very low ionic strength
Overview
Bovine beta-lactoglobulin (BLG) is a globular protein of uncertain physiological function and a member of the lipocalin superfamily of proteins. Here, we present the X-ray structure at 3.0 angstroms of BLG (variant A) from an orthorhombic (P2(1)2(1)2(1)) pseudo-tetragonal crystal form that suffers from pseudo-merohedral twinning (final R(working) = 0.224, R(free) = 0.265). Crystals were grown by dialysis against ultra-purified water (i.e., at very low ionic strength), at pH approximately 5.2 (approximately pI), conditions vastly different from all other BLG structures determined previously. This allows critical assessment of the BLG structure and of the influence that pH, ionic strength, and crystal packing may have on the molecular structure of BLG. The pH-sensitive EF loop is found in the closed conformation characteristic of BLG at pH less than 7 and moderate to high ionic strength. Although the hydrophobic pocket appears to be empty, the presence of highly disordered water molecules cannot be excluded. The dimer interface and the hydrophobic pocket (calyx) are preserved. However, the orientation of the subunits in the dimer varies considerably with crystal form. Structure is deposited with PDB ID 2akq.
About this Structure
2AKQ is a Single protein structure of sequence from Bos taurus. This structure supersedes the now removed PDB entry 1mfh. Full crystallographic information is available from OCA.
Reference
Structure of bovine beta-lactoglobulin (variant A) at very low ionic strength., Adams JJ, Anderson BF, Norris GE, Creamer LK, Jameson GB, J Struct Biol. 2006 Jun;154(3):246-54. Epub 2006 Feb 6. PMID:16540345 Page seeded by OCA on Wed May 28 09:27:38 2008
