6b3i

Annexin A13a

spinqualitylabelsall models 6b3i, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6b3i is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.6Å Ligands: EDO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ANX13_HUMAN Binds to membranes enriched in phosphatidylserine or phosphatidylglycerol in a calcium-dependent manner (PubMed:27676605, PubMed:30610115). Half-maximal membrane binding requires about 60 uM calcium. Does not bind to membranes that lack phospholipids with an acidic headgroup (PubMed:27676605). Binds to membranes enriched in phosphatidylserine or phosphatidylglycerol in a calcium-dependent manner, but requires higher calcium levels for membrane binding than isoform A. Half-maximal membrane binding requires about 320 uM calcium. Publication Abstract from PubMed Annexin proteins function as Ca(2+)-dependent regulators of membrane trafficking and repair that may also modulate membrane curvature. Here, using high-resolution confocal imaging, we report that the intestine-specific annexin A13 (ANX A13) localizes to the tips of intestinal microvilli and determined the crystal structure of the ANX A13a isoform to 2.6 A resolution. The structure revealed that the N terminus exhibits an alternative fold that converts the first two helices and the associated helix-loop-helix motif into a continuous alpha-helix, as stabilized by a domain-swapped dimer. We also found that the dimer is present in solution and partially occludes the membrane-binding surfaces of annexin, suggesting that dimerization may function as a means for regulating membrane binding. Accordingly, as revealed by in vitro binding and cellular localization assays, ANX A13a variants that favor a monomeric state exhibited increased membrane association relative to variants that favor the dimeric form. Together, our findings support a mechanism for how the association of the ANX A13a isoform with the membrane is regulated. An alternative N-terminal fold of the intestine-specific annexin A13a induces dimerization and regulates membrane-binding.,McCulloch KM, Yamakawa I, Shifrin DA Jr, McConnell RE, Foegeding NJ, Singh PK, Mao S, Tyska MJ, Iverson TM J Biol Chem. 2019 Mar 8;294(10):3454-3463. doi: 10.1074/jbc.RA118.004571. Epub, 2019 Jan 4. PMID:30610115 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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