A rapid MALDI-TOF mass spectrometry workflow for Drosophila melanogaster differential neuropeptidomics

Table 1 Peaks observed in MALDI-TOF MS profile spectra confirmed to be neuropeptides by MALDI-TOF/TOF MS/MS fragmentation

Obs. *m/z(Calc. m/z*)	Precursor (UniProtKB Entry name)	Peptide name	Peptide sequence	Previous ref.
925.481* (925.436)	FMRF_DROME	PDNFMRFamide	R.PDNFMRFa.G	[1, 2, 7, 9, 30]
974.592 (974.589)	SNPF_DROME	RLRF peptide 2	R.SPSLRLRFa.G	[1, 2, 9, 18, 19, 30]
1182.578 (1182.573)	FMRF_DROME	DPKQDFMRFamide (FMRFamide 2)	R.DPKQDFMRFa.G	[1, 2, 7, 9, 19, 30]
1247.658 (1247.653)	NEMS_DROME	Dromyosuppressin (TDVDHVFLRFamide)	R.TDVDHVFLRFa.G	[1, 2, 7, 9, 18, 19, 30]
1395.748 (1395.753)	Q59E62_DROME	SIFamide (IFa-1)	A.AYRKPPFNGSIFa.G	[1, 2, 9, 18, 19]
1430.745 (1430.754)	CP2B_DROME	CAP-3^AA2-AA15	T.GPSASSGLWFGPRLa.G	[1, 2, 9, 19, 30]
1471.791 (1471.773)	NPLP1_DROME	MTYamide peptide [NPLP1 (MTY)]	R.YIGSLARAGGLMTYa.G	[1, 2, 7, 9, 18, 19]
1531.812 (1531.802)	CP2B_DROME	CAP-3 (CAPA-3)	R.TGPSASSGLWFGPRLa.G	[1, 2, 9, 19, 30]
1534.819 (1534.834)	NPLP1_DROME	NPLP1-4 [NPLP1 (VQQ)]	R.NLGALKSSPVHGVQQ.K	[1, 2, 18, 19]
1653.907 (1653.908)	NPLP1_DROME	IPNamide [NPLP1 (IPN)]	R.NVGTLARDFQLPIPNa.G	[1, 2, 7, 9, 18, 19, 30]
1972.015 (1972.017)	PDF_DROME	Neuropeptide PDF	R.NSELINSLLSLPKNMNDAa.G	[19]
1991.044 (1991.043)	NPLP1_DROME	NPLP1-3^AA1-AA18 [QRAamide]	R.NVAAVARYNSQHGHIQRAa.G	Novel
2094.091 (2094.088)	NPLP1_DROME	NPLP1-2 [NPLP1 (DPK)]	R.NIATMARLQSAPSTHRDPK.R	Novel
2249.130 (2249.128)	NPLP1_DROME	NPLP1-3 [NPLP1 (GAE)]	R.NVAAVARYNSQHGHIQRAGAE.K	Novel

Listed are D. melanogaster neuropeptides identified in this study. The final three listings are believed to be novel. Reported observed m/z’s are the average of the m/z’s observed between the two replicate experiments MALDI-TOF MS experiments described. All observed m/z’s listed were determined to be monoisotopic [M + H]⁺’s of listed neuropeptides based on the calculated monoisotopic [M + H]⁺ (shown in parentheses below observed m/z). Truncated peptides are denoted by superscripts showing amino acids present from the annotated peptide sequence (i.e. NPLP1-3^AA1-AA18 is missing the final three residues of the annotated NPLP1-3 sequence, also shown). Peptide sequences include pre- and post- cleavage residues separated from sequences by a period. C-terminal amidation is denoted by an “a” at end of the peptide sequence. Abbreviations are listed in Table 2 legend. *m/z 925.481 likely corresponds to the convolution of PDNFMRFamide (monoisotopic [M + H]⁺ = 925.435) and Drostatin-3 (Ast-A3, monoisotopic [M + H]⁺ = 925.489, see Table 2), which were detected as separate peaks with MALDI-FTICR-MS (Figure 6), hence the comparatively larger m/z error.

ISSN: 1756-6606