--- title: "Aspartyl protease (HIV protease) Template | MolDraw" url: https://www.moldraw.com/templates/enzyme-hiv-protease/ description: "Aspartyl protease (HIV protease) template: In HIV-1 protease (a C2-symmetric dimer) one Asp25 carboxylate deprotonates a water molecule as it attacks the…" lang: en publisher: Scidart Academy generated: 2026-11-13 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Biochemistry](https://www.moldraw.com/templates/biochemistry/) › Aspartyl protease (HIV protease) [Biochemistry](https://www.moldraw.com/templates/biochemistry/)Premium # Aspartyl protease (HIV protease) template ![Aspartyl protease (HIV protease) template: In HIV-1 protease (a C2-symmetric dimer) one Asp25 carboxylate deprotonates a water molecule as it attacks the scissile carbonyl and Asp25′–H protonates the carbonyl oxygen, giving a neutral gem-diol; the roles then reverse to protonate the nitrogen and break the C–N bond.](https://www.moldraw.com/templates/enzyme-hiv-protease.webp) [Edit in MolDraw](https://www.moldraw.com/)Download with Pro Premium template. Preview and edit it free in MolDraw; downloading and exporting it is part of [MolDraw Pro](https://www.moldraw.com/pricing). In HIV-1 protease (a C2-symmetric dimer) one Asp25 carboxylate deprotonates a water molecule as it attacks the scissile carbonyl and Asp25′–H protonates the carbonyl oxygen, giving a neutral gem-diol; the roles then reverse to protonate the nitrogen and break the C–N bond. ## Mechanism step by step Two Asp25 side chains, one from each subunit, activate water: a tetrahedral gem-diol intermediate, then C–N cleavage 1. **Gem-diol** – Asp25⁻ deprotonates water as it attacks the C=O; Asp25′–H protonates the carbonyl O 2. **C–N cleavage** – Asp25′⁻ takes an OH proton, C=O re-forms, and the N takes H⁺ from Asp25–H as it leaves ## Key points - HIV protease is a homodimer: each 99-residue subunit gives one Asp25 (Asp-Thr-Gly motif) to the active site (Navia et al. 1989); pepsin and renin are single-chain aspartyl proteases. - No covalent enzyme intermediate forms; water is the nucleophile, unlike the serine and cysteine proteases. - Saquinavir, ritonavir and darunavir are transition-state mimics: a non-cleavable hydroxyethylene or hydroxyethylamine replaces the tetrahedral gem-diol. - The protease cuts the Gag and Gag-Pol polyproteins; blocking it gives immature, non-infectious virions. Drawn with 72 atoms, 11 arrows, 6 shapes – every one editable in MolDraw. ## Sources - [Nelson & Cox, Lehninger Principles of Biochemistry, 8th ed., 2021, ch. 6](https://openlibrary.org/isbn/9781319228002) Textbook - [Berg, Tymoczko, Gatto & Stryer, Biochemistry, 9th ed., 2019, ch. 9](https://openlibrary.org/isbn/9781319114657) Textbook - [Navia, Fitzgerald, McKeever, Leu, Heimbach, Herber, Sigal, Darke & Springer, Nature 1989, 337, 615](https://doi.org/10.1038/337615a0) Original paper ## How to use this template 1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor. 2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need. 3. Add your own structures, arrows and text next to it, or combine several templates on one page. 4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers. ## Frequently asked questions ### Is the Aspartyl protease (HIV protease) template free? You can preview the Aspartyl protease (HIV protease) template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates. ### Can I edit the Aspartyl protease (HIV protease) template? Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it. ### Is the chemistry checked? Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page. ### Are the biochemical pathways drawn with structures? Yes. 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