7eqz | pdb_00007eqz

Crystal structure of Carboxypeptidase B complexed with Potato Carboxypeptidase Inhibitor

spinqualitylabelsall models 7eqz, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7eqz is a 2 chain structure with sequence from Aedes aegypti and Solanum tuberosum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: GLY, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A1S4F020_AEDAE Publication Abstract from PubMed Metallocarboxypeptidases (MCPs) in the mosquito midgut play crucial roles in infection, as well as in mosquito dietary digestion, reproduction, and development. MCPs are also part of the digestive system of plant-feeding insects, representing key targets for inhibitor development against mosquitoes/mosquito-borne pathogens or as antifeedant molecules against plant-feeding insects. Notably, some non-mosquito insect B-type MCPs are primarily insensitive to plant protease inhibitors (PPIs) such as the potato carboxypeptidase inhibitor (PCI; MW 4 kDa), an inhibitor explored for cancer treatment and insecticide design. Here, we report the crystal structure of Aedes aegypti carboxypeptidase-B1 (CPBAe1)-PCI complex and compared the binding with that of PCI-insensitive CPBs. We show that PCI accommodation is determined by key differences in the active-site regions of MCPs. In particular, the loop regions alpha6-alpha7 (Leu(242) -Ser(250) ) and beta8-alpha8 (Pro(269) -Pro(280) ) of CPBAe1 are replaced by alpha-helices in PCI-insensitive insect Helicoverpa zea CPBHz. These alpha-helices protrude into the active-site pocket of CPBHz, restricting PCI insertion and rendering the enzyme insensitive. We further compared our structure with the only other PCI complex available, bovine CPA1-PCI. The potency of PCI against CPBAe1 (K(i) = 14.7 nM) is marginally less than that of bovine CPA1 (K(i) = 5 nM). Structurally, the above loop regions that accommodate PCI binding in CPBAe1 are similar to that of bovine CPA1, although observed changes in proteases residues that interact with PCI could account for the differences in affinity. Our findings suggest that PCI sensitivity is largely dictated by structural interference, which broadens our understanding of carboxypeptidase inhibition as a mosquito population/parasite control strategy. Structure of Aedes aegypti carboxypeptidase B1-inhibitor complex uncover the disparity between mosquito and non-mosquito insect carboxypeptidase inhibition mechanism.,Gavor E, Choong YK, Jobichen C, Mok YK, Kini RM, Sivaraman J Protein Sci. 2021 Dec;30(12):2445-2456. doi: 10.1002/pro.4212. Epub 2021 Nov 5. PMID:34658092 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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