Minimal motif peptide structure of metzincin clan zinc peptidases in micelles

Abstract

It is well known that the functions of metalloproteins generally originate from their metal-binding motifs. However, the intrinsic nature of individual motifs remains unknown, particularly the details about metal-binding effects on the folding of motifs; the converse is also unknown, although there is no doubt that the motif is the core of the reactivity for each metalloprotein. In this study, we focused our attention on the zinc-binding motif of the metzincin clan family, HEXXHXXGXXH; this family contains the general zinc-binding sequence His-Glu-Xaa-Xaa-His (HEXXH) and the extended GXXH region. We adopted the motif sequence of stromelysin-1 and investigated the folding properties of the Trp-labeled peptides WAHEIAHSLGLFHA (STR-W1), AWHEIAHSLGLFHA (STR-W2), AHEIAHSLGWFHA (STR-W11), and AHEIAHSLGLFHWA (STR-W14) in the presence and absence of zinc ions in hydrophobic micellar environments by circular dichroism (CD) measurements. We accessed successful incorporation of these zinc peptides into micelles using quenching of Trp fluorescence. Results of CD studies indicated that two of the Trp-incorporated peptides, STR-W1 and STR-W14, exhibited helical folding in the hydrophobic region of cetyltrimethylammonium chloride micelle. The NMR structural analysis of the apo STR-W14 revealed that the conformation in the C-terminus GXXH region significantly differred between the apo state in the micelle and the reported Zn-bound state of stromelysin-1 in crystal structures. The structural analyses of the qualitative Zn-binding properties of this motif peptide provide an interesting Zn-binding mechanism: the minimum consensus motif in the metzincin clan, a basic zinc-binding motif with an extended GXXH region, has the potential to serve as a preorganized Zn binding scaffold in a hydrophobic environment.

The unusual binding mechanism of Cu(ii) ions to the poly-histidyl domain of a peptide found in the venom of an African viper

“…2 The zinc-binding domain (-HEXXHXXGXXH-) is highly conserved in all of the metzincin clan of metalloendopeptidases (comprising the ADAM family) and contains three histidines separated by three and five residues. 4 The various crystal structures of SVMPs show that the three His residues and an oxygen atom of a water molecule are tetrahedrally coordinated to the zinc ion. 2 One of the most interesting questions that one can ask with regard to the strong proteolytic activity of SVMPs is: why does the venom not damage the venom glands of the snake?…”

Divalent metal ion modulation of a simple peptide-based hydrogel: self-assembly and viscoelastic properties

“…This may be due to stable species formation at this ratio of Cu 2+ which is supported by the presence of a 2 : 1 C 14 -FH(Trt)-OH : Cu complex species found through mass spectrometry as stated earlier. Based on these spectroscopic results suggesting involvement of the amide backbone and literature, 54,57–60 potential structures have been hypothesized and shown in Fig. 8 demonstrating a metal ion binding pocket potentially formed by the imidazole and amide backbone in addition to free aromatic rings to allow for self-assembly through π-interactions into supramolecular nanostructures.…”

Two-step functional screen on multiple proteinaceous substrates reveals temperature-robust proteases with a broad-substrate range

“…Both C3 and C6 are zinc-binding metalloproteases belonging to the MA clan, according to the MEROPS classification. They contain a signature HEXXH sequence, shown by crystallographic studies to form a metal-binding motif, and a glutamate, both important for catalysis (Onoda et al 2009). The C3 protease was present in TB1, TB2, and TB3 and the C6 protease was present in the MH1 clone.…”