Three-dimensional Structure of a Kunitz-type Inhibitor in Complex with an Elastase-like Enzyme

Abstract

Background: Kunitz-type inhibitors provide a suitable scaffold for novel elastase inhibitors. Results: The inhibitor ShPI-1 was modified for pancreatic elastase binding, and the crystal structure of the complex was elucidated and analyzed. Conclusion: The extended protease-inhibitor interactions provide a potential switch to direct inhibitor selectivity toward elastases. Significance: These results will help to design novel elastase inhibitors for the treatment of tissue destruction diseases.

A Low Molecular Weight Protein from the Sea Anemone <em>Anemonia viridis</em> with an Anti Angiogenic Activity

“…Another property of KTI is to have an active site with amphoteric characteristic as described in the crystal structure of a Caribbean sea anemone SHPI-1in a complex with an Elastase enzyme used in this study [18]. The amphoteric characteristic is due to a hydrophobic and a hydrophilic poles made of F16 and R11 for SHPI-1 (Fig 7C), and F16 and R12 for BDS-5 (Fig 7A).…”

“…A final energy minimization procedure made possible to obtain a final BDS-5 model 3D structure with a low van der Waals energy ( Figure 7). Kunitz-type structures are low molecular weight proteins characterized by a short alpha helix, a two beta strand sheet and three disulfide bridges as the SHPI-1 sea anemone protein [18]. Molecular modeling showed that it was possible to have a BDS-5 model 3D structure compatible with a Kunitz-type structure with disulfide bridges similar to BDS-1.…”

“…Panel A is the BDS-5 model 3D structure determined with molecular modeling from atomic coordinates of SHPI-1 [18] in Panel C. It was also possible to build a BDS-5 model from BDS-1 structure (panel B) since only one mutation F/L 18 existed between these two proteins but this model was not compatible with CD data. Although one disulfide bridge (colored in yellow) is different in SHPI-1 structure, molecular modeling showed that it was possible to have a BDS-5 model structure compatible with a Kunitz-type structure characterized by a C-terminal short alpha helix (colored in red).…”

“…Protein spectra are characterized by a first absorbance at 280 nm due to aromatic residues and then a major absorbance due to peptidic bonds that begins at 210 nm [16]. The elution time shows that these compounds were not retained in C8 column and confirmed that they were alkaloid pigments with aromatic cycles [18]. Semiprepartive HPLC made possible to collect nine main protein fractions.…”

“…It is interesting to note that F16 in the SHPI-1 crystal structure had also a similar position (Fig 7A&C). R11 and F18 in SHPI-1 were the residues involved in the inhibition of Elastase [18], and the BDS-5 3D structure model showed that R12 was located similarly to R11 in SHPI-1 (Fig 7A&C). The presence of a C terminal alpha helix induced a major change in the location of the…”