Premium
Fragmentation Studies of Gas‐phase Complexes Between Alkali Metal Ions and a Biologically Active Peptide, Achatin‐I
Author(s) -
Kenny Peter T. M.,
Nomoto Kyosuke,
Orlando Ron
Publication year - 1997
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19970131)11:2<224::aid-rcm733>3.0.co;2-u
Subject(s) - chemistry , carboxylate , peptide , fast atom bombardment , amino acid , stereochemistry , aspartic acid , fragmentation (computing) , achatina , dissociation (chemistry) , tandem mass spectrometry , ion , mass spectrometry , snail , chromatography , organic chemistry , biochemistry , ecology , computer science , biology , operating system
Achatin‐I is a tetrapeptide containing a d ‐amino acid and was isolated from the cerebral ganglia of the African giant snail Achatina fulica Ferussac. It may have a role as a neurotransmitter in the central nervous system, as it induced a voltage‐dependent inward current due to Na + on the identifiable giant neuron of the same snail. The amino acid sequence of achatin‐I was shown to be Gly‐ d ‐Phe‐Ala‐Asp. The peptide/metal‐ion binding interactions in the gas phase were investigated by fast‐atom bombardment mass spectrometry in combination with tandem mass spectrometry. Analysis of the collision‐induced dissociation (CID) spectrum of the [M + Na] + species of achatin‐I revealed that the sodium ion is bonded on the N‐terminal side and not at the deprotonated carboxylate terminus. The [M + 2Na–H] + complex of achatin‐I was also subjected to CID measurements. This revealed that the location of the second sodium ion was at one of the depronated carboxylate groups of the aspartic acid residue. Another peptide with the same sequence, but consisting of l ‐amino acids was isolated from the ganglia of the same snail but was devoid of biological activity. To determine whether the d ‐phenylalanine residue influenced the location of the sodium ion the CID spectra of both the [M + Na] + and the [M + 2Na–H] + ion species of GFAD were recorded; they were practically identical to the CID spectra of the [M + Na] + and the [M + 2Na–H] + ion species of Gly‐ d ‐Phe‐Ala‐Asp. © 1997 John Wiley & Sons, Ltd.