Structure of the ABC ATPase domain of human TAP1, the transporter associated with antigen processing
Structure of the ABC ATPase domain of human TAP1, the transporter associated with antigen processing
复制标题
DOI：
10.1093/emboj/20.17.4964
复制
发表时间：
2001-09-03
期刊：
影响因子：
11.4
通讯作者：
Wiley, DC
中科院分区：
文献类型：
--
作者：
Gaudet, R;Wiley, DC
与抗原加工相关的转运蛋白（TAP）是一种ABC转运蛋白，由TAP 1和TAP 2两个亚基组成，每个亚基都有一个N端跨膜结构域和一个C端ABC ATP酶结构域。我们报告的结构的C-末端ABC ATP酶域的TAP 1（cTAP 1）绑定到ADP。cTAP 1形成具有两个结构域的L形分子，RecA样结构域和小的α-螺旋结构域。ADP的二磷酸基团如预期的那样与P环相互作用。被认为参与γ-磷酸结合和水解的残基在ADP结合状态下显示出灵活性，如其高B因子所证明的。cTAP 1与ABC转运蛋白家族的其他ABC ATP酶以及参与DNA维持和修复的ABC ATP酶的比较揭示了每个家族特异性的关键区域和残基。三个ATP酶亚家族被确定具有不同的腺苷识别基序，以及不同的子域，可能是特定的每个亚家族的不同功能。TAP 1和TAP 2在核苷酸结合位点的差异可能与肽转运过程中观察到的不对称性有关。
The transporter associated with antigen processing (TAP) is an ABC transporter formed of two subunits, TAP1 and TAP2, each of which has an N-terminal membrane-spanning domain and a C-terminal ABC ATPase domain. We report the structure of the C-terminal ABC ATPase domain of TAP1 (cTAP1) bound to ADP. cTAP1 forms an L-shaped molecule with two domains, a RecA-like domain and a small a-helical domain. The diphosphate group of ADP interacts with the P-loop as expected. Residues thought to be involved in gamma -phosphate binding and hydrolysis show flexibility in the ADP-bound state as evidenced by their high B-factors. Comparisons of cTAP1 with other ABC ATPases from the ABC transporter family as well as ABC ATPases involved in DNA maintenance and repair reveal key regions and residues specific to each family. Three ATPase subfamilies are identified which have distinct adenosine recognition motifs, as well as distinct subdomains that may be specific to the different functions of each subfamily. Differences between TAP1 and TAP2 in the nucleotide-binding site may be related to the observed asymmetry during peptide transport.