TY  - JOUR
A1  - Ernst, Robert
A1  - Koch, Joachim
A1  - Horn, Carsten
A1  - Tampé, Robert
A1  - Schmitt, Lutz
T1  - Engineering ATPase activity in the isolated ABC cassette of human TAP1
T2  - Journal of biological chemistry
N2  - The human transporter associated with antigen processing (TAP) translocates antigenic peptides from the cytosol into the endoplasmic reticulum lumen. The functional unit of TAP is a heterodimer composed of the TAP1 and TAP2 subunits, both of which are members of the ABC-transporter family. ABC-transporters are ATP-dependent pumps, channels, or receptors that are composed of four modules: two nucleotide-binding domains (NBDs) and two transmembrane domains (TMDs). Although the TMDs are rather divergent in sequence, the NBDs are conserved with respect to structure and function. Interestingly, the NBD of TAP1 contains mutations at amino acid positions that have been proposed to be essential for catalytic activity. Instead of a glutamate, proposed to act as a general base, TAP1 contains an aspartate and a glutamine instead of the conserved histidine, which has been suggested to act as the linchpin. We used this degeneration to evaluate the individual contribution of these two amino acids to the ATPase activity of the engineered TAP1-NBD mutants. Based on our results a catalytic hierarchy of these two fundamental amino acids in ATP hydrolysis of the mutated TAP1 motor domain was deduced.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76230
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-762304
SN  - 0021-9258
VL  - 281.2006
IS  - 37
SP  - 27471
EP  - 27480
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -