4U02: Crystal Structure Of Apo-ttha1159

Citation:
Abstract
ATP-binding cassette (ABC) transporters are a major family of small molecule transporter proteins, and their deregulation is associated with several diseases, including cancer. Here, we report the crystal structure of the nucleotide binding domain (NBD) of an amino acid ABC transporter from Thermus thermophilus (TTHA1159) in its apo form and as a complex with ADP along with functional studies. TTHA1159 is a putative arginine ABC transporter. The apo-TTHA1159 was crystallized in dimeric form, a hitherto unreported form of an apo NBD. Structural comparison of the apo and ADP-Mg(2+) complexes revealed that Phe14 of TTHA1159 undergoes a significant conformational change to accommodate ADP, and that the bound ADP interacts with the P-loop (Gly40-Thr45). Modeling of ATP-Mg(2+):TTHA1159 complex revealed that Gln86 and Glu164 are involved in water-mediated hydrogen bonding contacts and Asp163 in Mg(2+) ion-mediated hydrogen bonding contacts with the gamma-phosphate of ATP, consistent with the findings of other ABC transporters. Mutational studies confirmed the necessity of each of these residues, and a comparison of the apo/ADP Mg(2+):TTHA1159 with its ATP-complex model suggests the likelihood of a key conformational change to the Gln86 side chain for ATP hydrolysis.
PDB ID: 4U02Download
MMDB ID: 129232
PDB Deposition Date: 2014/7/11
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
Similar Structures:
Biological Unit for 4U02: monomeric; determined by author and by software (PISA)
Molecular Components in 4U02
Label Count Molecule
Protein (1 molecule)
1
Amino Acid ABC Transporter, Atp-binding Protein
Molecule annotation
Chemical (1 molecule)
1
1
* Click molecule labels to explore molecular sequence information.

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