The active site of the homodimeric HIV-1 protease includes six amino acids (triads AspThrGly found in each monomer) in amino acid positions 25 to 27 and 25' to 27'. Up to now, the role of Thr26 and Thr26', and Gly27 and Gly27', is unknown. It is hypothesized that strong hydrogen-bonding forces between the Thr26 and Thr26' residues stabilize the conformational state of the active site, and that the function of Gly27 and Gly27' is to accommodate and bind a substrate in a position in which the catalytic Asp25 and Asp25' carboxylate groups can attack the amide moiety of a substrate.

中文翻译：

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HIV-1蛋白酶的活性位点。

同型二聚体HIV-1蛋白酶的活性位点在25至27和25'至27'的氨基酸位置包含六个氨基酸（在每个单体中发现的三联体AspThrGly）。到目前为止，Thr26和Thr26'以及Gly27和Gly27'的作用尚不清楚。据推测，Thr26和Thr26'残基之间强大的氢键力稳定了活性位点的构象状态，并且Gly27和Gly27'的功能是在催化Asp25和Asp25'羧酸酯基团可以攻击底物的酰胺部分。