The figure was created using Swiss-pbd viewer (Guex & Peitsch, 1997) and pov-ray (). Although LlinCSP6 and LhesCSP6 are 98% identical (four amino acid differences), the residues affected reside in portions of the sequence that were not modeled. LlinCSP1 and LhesCSP1 are 100% identical as is LlinCSP3 and LhesCSP3, thus only one model is shown for each set. Based on the spatial coordinates used to generate the respective models, the amino acid insertion between C3 and C4 in LlinCSP6/LhesCSP6 prevented formation of the characteristic disulfide bridge. The lack of a helix 6 and substitution of amino acids with smaller sidechains likely contributes to a larger binding pocket in LlinCSP1/LhesCSP1. The residues predicted to comprise the binding pocket, which is based on distance criteria (<5Å<5˚<5Å) generated from a ligand bound MbraCSP6 structure, are shown in purple and depicted in stick mode. The lower panel shows differences in size of the putative binding pocket. The Cys residues and accompanying disulfide bonds are colored yellow and are likewise depicted in stick mode. The Tyr residue in helix 2 that is predicted to form the bottom of the channel is colored bright pink and depicted in stick mode. The upper panel shows different perspectives of the respective models with the front and bottom views indicated. Helical segments are color-coded: helix 1, light blue helix 2, light purple helix 3, turquoise helix 4, orange helix 5, light green, and helix 6, light pink. Homology-based conformations for a typical (LlinCSP3/LhesCSP3) and two atypical (LlinCSP1/LhesCSP1 and LlinCSP6/LhesCSP6) CSPs are shown along with the MbraCSP6 solution structure used to generate the respective models. Ribbon model representation of Lygus CSP structures. Comparative sequence analyses and homology modeling suggest that variations in the amino acids that comprise the Lygus CSP binding pockets affects the size and nature of the ligands accommodated. lineolaris tissues revealed broad expression for most of the CSPs with antenna specific expression limited to a subset of the CSPs. Reverse transcriptase PCR‐based profiling of CSP transcript abundance in adult L. The seven helix CSP is further differentiated by an atypical C3‐X3‐C4 Cys spacing motif. Three of the CSPs are predicted to deviate from the typical CSP structure with either five or seven helical segments rather than six. The Lygus CSPs are orthologous and share significant sequence identity with previously annotated CSPs. To expand our molecular understanding of CSP function in plant bugs, we used recently developed transcriptomic resources for Lygus lineolaris and Lygus hesperus to identify 17 and 14 CSP‐like sequences, respectively. CSPs are functionally diverse with reported roles in chemosensation, immunity, development, and resistance. Chemosensory proteins (CSPs) are soluble carrier proteins typically characterized by a six‐helix bundle structure joined by two disulfide bridges and a conserved Cys spacing pattern (C1‐X6‐8‐C2‐X16‐21‐C3‐X2‐C4).
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