Solution structure of the toxic octapeptide, lophyrotomin

DALY N.L., ATKINS A.R. and SMITH R. (1993) Solution structure of the toxic octapeptide, lophyrotomin. International Journal of Peptide and Protein Research, 42 4: 366-371. doi:10.1111/j.1399-3011.1993.tb00506.x

Author DALY N.L.
Title Solution structure of the toxic octapeptide, lophyrotomin
Journal name International Journal of Peptide and Protein Research   Check publisher's open access policy
ISSN 1399-3011
Publication date 1993-01-01
Sub-type Article (original research)
DOI 10.1111/j.1399-3011.1993.tb00506.x
Open Access Status Not yet assessed
Volume 42
Issue 4
Start page 366
End page 371
Total pages 6
Language eng
Subject 1303 Biochemistry
Abstract Lophyrotomin is a toxic octapeptide, first isolated from larvae of the sawfly Lophyrotoma interrupta, which causes the death of cattle and sheep. It appears to act principally‐ on the liver, however very little is known about the cellular site and mechanism of action. In the present study lophyrotomin was synthesized using solid‐phase peptide synthesis and the structure examined with two‐dimensional nuclear magnetic resonance (NMR) spectroscopy. Two‐dimensional correlation experiments (COSY and TOCSY) enabled the assignment of many of the resonances. Conventional NOESY experiments did not produce inter‐residue information, however the alternative rotating frame NOE experiment (ROESY) resulted in intra‐residue αN, and sequential αN and NN NOES, permitting the sequence‐specific assignment of all resonances. The presence of few additional short‐range NOES and the absence of any long‐range NOES in the ROESY spectra indicated a lack of persistent secondary structure. The results from circular dichroism (CD) spectroscopy experiments were consistent with the NOE data, as addition of high concentrations of the denaturant urea produced no changes in the lophyrotomin CD spectrum. This conclusion was further supported by C spin‐lattice relaxation studies, which indicated that the peptide is a flexible molecule by examination of the α‐carbon chemical shifts, and by amide proton exchange rate measurements. Consequently it appears that if this peptide has to adopt a well defined structure to exert its biological activity it must do so on interaction with other molecules, such as a receptor. Copyright
Keyword circular dichroism
Lophyrotoma interrupta
nuclear magnetic resonance
peptide conformation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
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