2IXE

Crystal structure of the ATPase domain of TAP1 with ATP (D645N mutant)

Summary for 2IXE

• Entry DOI: 10.2210/pdb2ixe/pdb
• Related: 2IXF 2IXG
• Descriptor: ANTIGEN PEPTIDE TRANSPORTER 1, ADENOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: abc atpase, hydrolase
• Biological source: RATTUS NORVEGICUS (RAT)
• Total number of polymer chains: 2
• Total formula weight: 60122.83

Authors

Procko, E.,Ferrin-O'Connell, I.,Ng, S.-L.,Gaudet, R. (deposition date: 2006-07-07, release date: 2006-10-11, Last modification date: 2023-12-13)

Primary citation

Procko, E.,Ferrin-O'Connell, I.,Ng, S.-L.,Gaudet, R.
Distinct Structural and Functional Properties of the ATPase Sites in an Asymmetric Abc Transporter.
Mol.Cell, 24:51-, 2001

PubMed Abstract: The ABC transporter associated with antigen processing (TAP) shuttles cytosolic peptides into the endoplasmic reticulum for loading onto class I MHC molecules. Transport is fueled by ATP binding and hydrolysis at two distinct cytosolic ATPase sites. One site comprises consensus motifs shared among most ABC transporters, while the second has substituted, degenerate motifs. Biochemical and crystallography experiments with a TAP cytosolic domain demonstrate that the consensus ATPase site has high catalytic activity and facilitates ATP-dependent dimerization of the cytosolic domains, which is an important conformational change during transport. In contrast, the degenerate site is defective in dimerization and ATP hydrolysis. Full-length TAP mutagenesis demonstrates the necessity for at least one consensus site, supporting our conclusion that the consensus site is the principal facilitator of substrate transport. Since asymmetry of the ATPase site motifs is a feature of many mammalian homologs, our proposed model has broad implications for ABC transporters.

PubMed: 17018292
DOI: 10.1016/J.MOLCEL.2006.07.034

Experimental method

X-RAY DIFFRACTION (2 Å)