Next generation sequencing and de novo transcriptomics to study gene evolution

Table 4 Zinnia haageana PDPs matching masses observed in the LC-MS profile

Peptide sequence	Predicted mass (Da)	Observed mass (Da)	LC matches synthetic
GICFKDPFGSTLCAPY	858.88	858.86	Yes
cyclo-GICFKDPFGSTLCAPD	825.86	825.88	Yes
cyclo-GQCEILPWFPFPEACGPD	993.43	993.43	Yes
cyclo-GPCYSYQSCFPD	673.75	673.75	Yes
cyclo-GRPCYTLQSCFPD	733.81	733.83	Yes
cyclo-GLCTILPWPPYLEVCGLD	984.98	984.98	Yes
cyclo-GPCFPMGPWGPFCIPD	850.86	850.86	Yes
cyclo-GRGCFGFPPICFPD	746.83	746.83	ND
cyclo-SAACSHLPPGLREMCAAWSFD	1114.99	1114.97	ND
cyclo-SAACSHLQPVLREMCVARFD	1107.02	1107.01	ND
cyclo-GAACSHIEPGLREMCAAWSFFD	1189.51	1189.48	ND

The predicted mass is for the doubly charged [M⁺²] ion and assumes the Cys residues form a disulfide bond (oxidised). For cyclic peptides the monoisotopic mass is reduced by 18 Da. The observed masses from LC-MS experiments are calculated from the doubly charged [M⁺²] ions. Seven synthetic peptides were ordered, which allowed additional confirmation of the retention time of the mass during liquid chromatography (LC). The retention times for some masses were not confirmed using synthetic peptides (ND).

ISSN: 1746-4811