2DG2

Crystal Structure of Mouse Apolipoprotein A-I Binding Protein

Summary for 2DG2

• Entry DOI: 10.2210/pdb2dg2/pdb
• Descriptor: Apolipoprotein A-I binding protein, SULFATE ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: disordered n-terminus, protein binding
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 6
• Total formula weight: 179745.50

Authors

Shumilin, I.A.,Jha, K.N.,Zheng, H.,Chruszcz, M.,Cymborowski, M.,Herr, J.C.,Minor, W. (deposition date: 2006-03-08, release date: 2007-03-27, Last modification date: 2024-11-20)

Primary citation

Jha, K.N.,Shumilin, I.A.,Digilio, L.C.,Chertihin, O.,Zheng, H.,Schmitz, G.,Visconti, P.E.,Flickinger, C.J.,Minor, W.,Herr, J.C.
Biochemical and structural characterization of apolipoprotein A-I binding protein, a novel phosphoprotein with a potential role in sperm capacitation.
Endocrinology, 149:2108-2120, 2008

PubMed Abstract: The physiological changes that sperm undergo in the female reproductive tract rendering them fertilization-competent constitute the phenomenon of capacitation. Cholesterol efflux from the sperm surface and protein kinase A (PKA)-dependent phosphorylation play major regulatory roles in capacitation, but the link between these two phenomena is unknown. We report that apolipoprotein A-I binding protein (AI-BP) is phosphorylated downstream to PKA activation, localizes to both sperm head and tail domains, and is released from the sperm into the media during in vitro capacitation. AI-BP interacts with apolipoprotein A-I, the component of high-density lipoprotein involved in cholesterol transport. The crystal structure demonstrates that the subunit of the AI-BP homodimer has a Rossmann-like fold. The protein surface has a large two compartment cavity lined with conserved residues. This cavity is likely to constitute an active site, suggesting that AI-BP functions as an enzyme. The presence of AI-BP in sperm, its phosphorylation by PKA, and its release during capacitation suggest that AI-BP plays an important role in capacitation possibly providing a link between protein phosphorylation and cholesterol efflux.

PubMed: 18202122
DOI: 10.1210/en.2007-0582

Experimental method

X-RAY DIFFRACTION (2.45 Å)