2l6q

New high resolution NMR structure of gpW (W protein of bacteriophage lambda) at neutral pH

spinqualitylabelsall models 2l6q Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2l6q is a 1 chain structure with sequence from Escherichia virus Lambda. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function HCP_LAMBD Plays a role in morphogenesis of the virion head after genome packaging. Presumably interacts with the portal vertex to stabilize the packaged DNA within the head after packaging. Probably binds to the head-tail connector protein FII. Publication Abstract from PubMed GpW is a 68-residue protein from bacteriophage lambda that participates in virus head morphogenesis. Previous NMR studies revealed a novel alpha+beta fold for this protein. Recent experiments have shown that gpW folds in microseconds by crossing a marginal free energy barrier (i.e., downhill folding). These features make gpW a highly desirable target for further experimental and computational folding studies. As a step in that direction, we have re-determined the high-resolution structure of gpW by multidimensional NMR on a construct that eliminates the purification tags and unstructured C-terminal tail present in the prior study. In contrast to the previous work, we have obtained a full manual assignment and calculated the structure using only unambiguous distance restraints. This new structure confirms the alpha+beta topology, but reveals important differences in tertiary packing. Namely, the two alpha-helices are rotated along their main axis to form a leucine zipper. The beta-hairpin is orthogonal to the helical interface rather than parallel, displaying most tertiary contacts through strand 1. There also are differences in secondary structure: longer and less curved helices and a hairpin that now shows the typical right-hand twist. Molecular dynamics simulations starting from both gpW structures, and calculations with CS-Rosetta, all converge to our gpW structure. This confirms that the original structure has strange tertiary packing and strained secondary structure. A comparison of NMR datasets suggests that the problems were mainly caused by incomplete chemical shift assignments, mistakes in NOE assignment and the inclusion of ambiguous distance restraints during the automated procedure used in the original study. The new gpW corrects these problems, providing the appropriate structural reference for future work. Furthermore, our results are a cautionary tale against the inclusion of ambiguous experimental information in the determination of protein structures. Revisiting the NMR structure of the ultrafast downhill folding protein gpW from bacteriophage lambda.,Sborgi L, Verma A, Munoz V, de Alba E PLoS One. 2011;6(11):e26409. doi: 10.1371/journal.pone.0026409. Epub 2011 Nov 4. PMID:22087227 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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