4kvv

Crystal structure of an alkylated Cys mutant of CC-Hex

spinqualitylabelsall models 4kvv, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4kvv is a 12 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 4BF, ACE, YCM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Ab initio design of enzymes requires precise and predictable positioning of reactive functional groups within accessible and controlled environments of de novo protein scaffolds. Here we show that multiple thiol moieties can be placed within a central channel, with approximate dimensions 6 x 42 A, of a de novo, six-helix peptide assembly (CC-Hex). Layers of six cysteine residues are introduced at two different sites approximately 6 (the "L24C" mutant) and approximately 17 A (L17C) from the C-terminal opening of the channel. X-ray crystal structures confirm the mutant structures as hexamers with internal free thiol, rather than disulfide-linked cysteine residues. Both mutants are hexa-alkylated upon addition of iodoacetamide, demonstrating accessibility and full reactivity of the thiol groups. Comparison of the alkylation and unfolding rates of the hexamers indicates that access is directly through the channel and not via dissociation and unfolding of the assembly. Moreover, neither mutant reacts with iodoacetic acid, demonstrating selectivity of the largely hydrophobic channel. These studies show that it is possible to engineer reactive side chains with both precision and control into a de novo scaffold to produce protein-like structures with chemoselective reactivity. Accessibility, Reactivity, and Selectivity of Side Chains within a Channel of de Novo Peptide Assembly.,Burton AJ, Thomas F, Agnew C, Hudson KL, Halford SE, Brady RL, Woolfson DN J Am Chem Soc. 2013 Aug 13. PMID:23924058 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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