4ZR2

Crystal Structure of the Domain-Swapped Dimer K40L:Q108K:Y60W mutant of Human Cellular Retinol Binding Protein II

Summary for 4ZR2

• Entry DOI: 10.2210/pdb4zr2/pdb
• Related: 4QZT 4QZU 4ZH6 4ZH9
• Descriptor: Retinol-binding protein 2, RETINAL, ACETATE ION, ... (4 entities in total)
• Functional Keywords: domain swapped dimer, domain swapping, protein folding, human cellular retinol binding protein ii, intracellular lipid binding protein, retinal, lipid binding protein
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 2
• Total formula weight: 31790.69

Authors

Assar, Z.,Nossoni, Z.,Geiger, J.H. (deposition date: 2015-05-11, release date: 2016-06-08, Last modification date: 2024-10-30)

Primary citation

Assar, Z.,Nossoni, Z.,Wang, W.,Santos, E.M.,Kramer, K.,McCornack, C.,Vasileiou, C.,Borhan, B.,Geiger, J.H.
Domain-Swapped Dimers of Intracellular Lipid-Binding Proteins: Evidence for Ordered Folding Intermediates.
Structure, 24:1590-1598, 2016

PubMed Abstract: Human Cellular Retinol Binding Protein II (hCRBPII), a member of the intracellular lipid-binding protein family, is a monomeric protein responsible for the intracellular transport of retinol and retinal. Herein we report that hCRBPII forms an extensive domain-swapped dimer during bacterial expression. The domain-swapped region encompasses almost half of the protein. The dimer represents a novel structural architecture with the mouths of the two binding cavities facing each other, producing a new binding cavity that spans the length of the protein complex. Although wild-type hCRBPII forms the dimer, the propensity for dimerization can be substantially increased via mutation at Tyr60. The monomeric form of the wild-type protein represents the thermodynamically more stable species, making the domain-swapped dimer a kinetically trapped entity. Hypothetically, the wild-type protein has evolved to minimize dimerization of the folding intermediate through a critical hydrogen bond (Tyr60-Glu72) that disfavors the dimeric form.

PubMed: 27524203
DOI: 10.1016/j.str.2016.05.022

Experimental method

X-RAY DIFFRACTION (1.8024 Å)