A new peptide from Jatropha curcas seeds: Unusual sequence and insights into its synthetic analogue that enhances proteolytic activity of papain

Abstract

Please cite this article in press as: Jucá TL, et al. A new peptide from Jatropha curcas seeds: Unusual sequence and insights into its synthetic analogue that enhances proteolytic activity of papain. Process Biochem (2015), http://dx. a b s t r a c tA new peptide (1341 g/mol) from Jatropha curcas seeds was isolated. The linear sequence (APTLSG-GSVPRDAD) was deduced by de novo peptide sequencing, and further used as scaffold for synthesis of linear (1342 g/mol) and cyclic (1324 g/mol) synthetic analogues. The full peptide sequence was identified as inserted in a putative conserved domain of late-embryogenesis proteins which produced a significant alignment hit (100% of identity and E-value of 1e−05) with a hypothetical protein JCGZ 12502 of J. curcas. Whereas in the linear peptide predominated the double charged ion state (m/z 671.68), in the cyclic form was observed the mono charged ion state (m/z of 1325.19) and an unusual MS/MS fragmentation pattern. The differences between the forms were discrete in terms of ionic mobility, retention time (reverse phase) and net charge as function of pH. Circular dichroism spectra presented an intense negative peak at 198 nm which is assigned for its disordered contents. A negative peak at 222 nm in the spectrum of the circular form suggested its structure was not as disordered as the linear form. The peptides were neither haemolytic nor cytotoxic and did not inhibit phytopathogenic fungi. Surprisingly, the circular but not the linear peptide increased the proteolytic activity of papain.

Insights on the inhibition properties ofJatromollistatin(a cyclic heptapeptide) againstCrotalus adamanteusmetalloendopeptidase using molecular docking analysis

“…All SPE fractions containing 10%, 20%, 30%, 40%, 50%, 60%, 70%, and 80% ACN were monitored by absorbance at 216 and 280 nm. All fractions were then lyophilized and frozen at −20°C until use 17 …”

“…14 Despite the successful combination with the NCBI non-redundant protein sequence (nr) database, further studies involving synthetic analogs will be necessary to understand its biological functions. 16,17 However, it is noteworthy that almost all accessions identified are related to laticiferous plants (Table 3), which suggests, from an evolutionary perspective, a conserved function for this orbitide.…”

“…The isolation and identification of these orbitides, even from recognized sources such as Jatropha , are an arduous task. However, in recent years, nanofractionation and proteomics approaches have been used to investigate these polypeptide sequences 17,18 …”

“…However, in recent years, nanofractionation and proteomics approaches have been used to investigate these polypeptide sequences. 17,18 In the present study, a nanofractionation and proteomics approach was performed to detect and isolate a cyclic heptapeptide (named Jatromollistatin) from the latex of Jatropha molissima. Jatromollistatin is the first cyclotide reported so far for this species (previously reported for Jatropha curcas and Jatropha pohliana 19,20 ).…”

Biologically Active Orbitides from the Euphorbiaceae Family

“…In addition to the presence of cyclic peptides in the latex of J. curcas L., an investigation of the seeds led to the isolation of a new linear peptide named PII-C, consisting of 14 amino acid residues and having a molecular mass of 1341.58 Da [M + H] + . The amino acid sequence was found to be Ala-Pro-Thr-Leu-Ser-Gly-Gly-Ser-Val-Pro-Arg-Asp-Ala-Asp [81].…”