PDBsum entry 4omx

Transport protein

PDB id: 4omx

Contents

Protein chain

162 a.a.

Ligands

SO4 ×2

URE ×3

ARF ×2

Waters ×161

PDB id:

4omx

Name:

Transport protein

Title:

Crystal structure of goat beta-lactoglobulin (trigonal form)

Structure:

Beta-lactoglobulin. Chain: a. Synonym: beta-lg

Source:

Capra hircus. Domestic goat, goats. Organism_taxid: 9925

Resolution:

2.30Å R-factor: 0.196 R-free: 0.240

Authors:

J.I.Loch,S.Swiatek,M.Czub,M.Ludwikowska,K.Lewinski

Key ref:

J.I.Loch et al. (2015). Conformational variability of goat β-lactoglobulin: crystallographic and thermodynamic studies. Int J Biol Macromol, 72, 1283-1291. PubMed id: 25450833 DOI: 10.1016/j.ijbiomac.2014.10.031

Date:

27-Jan-14 Release date: 19-Nov-14

Protein chain

P02756  (LACB_CAPHI) -  Beta-lactoglobulin from Capra hircus

Seq: 180 a.a.

Struc: 162 a.a.

DOI no: 10.1016/j.ijbiomac.2014.10.031

Int J Biol Macromol 72:1283-1291 (2015)

PubMed id: 25450833

Conformational variability of goat β-lactoglobulin: crystallographic and thermodynamic studies.

J.I.Loch, P.Bonarek, A.Polit, S.Świątek, M.Czub, M.Ludwikowska, K.Lewiński.

ABSTRACT

Goat β-lactoglobulin (GLG), lipocalin protein sharing high sequence similarity to bovine β-lactoglobulin (BLG), has been structurally and thermodynamically characterized. Two crystal forms of GLG have been obtained, trigonal (P3121) and orthorhombic (P21212), with unique molecular packing, not observed previously for BLG. In the trigonal structure, GLG molecules have EF-loop in closed conformation while in the orthorhombic structure, for the first time, symmetric and asymmetric dimers of β-lactoglobulin are observed simultaneously. It indicates that the opening or closing EF-loop does not occur in both subunits at the same time but might be sequential and cooperative. Comparison of GLG and BLG structures revealed presence of various conformers of EF and GH. ITC studies showed that at pH 7.5 GLG binds sodium dodecyl sulfate with Gibbs energy similar to BLG, however, with different contribution from enthalpic and entropic component. At pH 7.5 GLG forms dimers with dimerization constant Ka=34.28×10(3)M(-1), significantly higher than observed for BLG. Similar mechanism of conformational changes and ligand binding indicates that GLG and BLG may play analogous biological role.