Crystal structure at pH 9.0 of a potato STI-Kunitz bi-functional inhibitor of serine and aspartic proteases in space group p4322 and ph 9.0Crystal structure at pH 9.0 of a potato STI-Kunitz bi-functional inhibitor of serine and aspartic proteases in space group p4322 and ph 9.0

Structural highlights

5fnx is a 1 chain structure with sequence from Solanum tuberosum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.65Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

M1AKE5_SOLTU

Publication Abstract from PubMed

Bi-functional inhibitors from the Kunitz-type soybean trypsin inhibitor (STI) family are glycosylated proteins able to inhibit serine and aspartic proteases. Here we report six crystal structures of the wild-type and a non-glycosylated mutant of the bifunctional inhibitor E3Ad obtained at different pH values and space groups. The crystal structures show that E3Ad adopts the typical beta-trefoil fold of the STI family exhibiting some conformational changes due to pH variations and crystal packing. Despite the high sequence identity with a recently reported potato cathepsin D inhibitor (PDI), three-dimensional structures obtained in this work show a significant conformational change in the protease-binding loop proposed for aspartic protease inhibition. The E3Ad binding loop for serine protease inhibition is also proposed, based on structural similarity with a novel non-canonical conformation described for the double-headed inhibitor API-A from the Kunitz-type STI family. In addition, structural and sequence analyses suggest that bifunctional inhibitors of serine and aspartic proteases from the Kunitz-type STI family are more similar to double-headed inhibitor API-A than other inhibitors with a canonical protease-binding loop.

Structures of a bi-functional Kunitz-type STI family inhibitor of serine and aspartic proteases: Could the aspartic protease inhibition have evolved from a canonical serine protease-binding loop?,Guerra Y, Valiente PA, Pons T, Berry C, Rudino-Pinera E J Struct Biol. 2016 Aug;195(2):259-71. doi: 10.1016/j.jsb.2016.06.014. Epub 2016 , Jun 18. PMID:27329566[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Guerra Y, Valiente PA, Pons T, Berry C, Rudino-Pinera E. Structures of a bi-functional Kunitz-type STI family inhibitor of serine and aspartic proteases: Could the aspartic protease inhibition have evolved from a canonical serine protease-binding loop? J Struct Biol. 2016 Aug;195(2):259-71. doi: 10.1016/j.jsb.2016.06.014. Epub 2016 , Jun 18. PMID:27329566 doi:http://dx.doi.org/10.1016/j.jsb.2016.06.014

5fnx, resolution 2.65Å

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