Peptide data on the disulfide bond analysis of baculovirus produced Pfs25 by LC-MSMS

This article contains the peptide data obtained while performing disulfide bond mapping of the recombinant Plasmodium falciparum protein, Pfs25, produced from the baculovirus expression system. Pfs25 is a malaria transmission-blocking vaccine candidate, with a compact and complex structure including 22 cysteines. This supplementary data is related to the research “Disulfide bond mapping of Pfs25, a recombinant malaria transmission blocking vaccine candidate” (Lee et al., 2018) [1]. In brief, Pfs25 was digested with trypsin/Lys-C and derived peptides separated by High Performance Liquid Chromatography (HPLC) and analyzed by mass spectrometry (MS) by MSE fragmentation. The theoretical peptides and their respective masses along with disulfide bond locations with linked peptides are presented here alongside the mass spectrometry analysis. The raw mass spectrometry data is made available through the Mass Spectrometry Interactive Virtual Environment (MassIVE) with identifier: MSV000081982.


Value of the data
The derived peptides and mass spectrometry data is provided here for further details from the disulfide bond analysis of Pfs25.
The disulfide bond locations and linked peptides are discussed alongside the mass spectrometry analysis here and data made accessible to the scientific community.
Pfs25 is a compact and complex 17.9 kDa protein with 22 cysteines (11 disulfide bonds) that has presented difficulty in prior disulfide bond analysis A method was developed to map the disulfide bonds of a complex and compact protein, which may be applicable to other proteins, an important step in recombinant protein development for vaccines.

Data
The Pfs25 disulfide bond mapping peptides are discussed in further detail in this manuscript to further support the elucidation of disulfide bonds of Pfs25 as discussed in [1]. Further, the mass spectrometry RAW files have been deposited in the Mass Spectrometry Interactive Virtual Environment (MassIVE). Theoretical peptides, produced from Trypsin/Lys-C digestion of Pfs25, are presented in Table 1.
Utilizing Biopharmalynx 1.3 the mass spectral data was analyzed and compared to the theoretical peptides to obtain the localization of the 11 disulfide bonds present in the recombinant Pfs25. The disulfide bond locations and linked peptides (including theoretical and observed) masses are presented in Table 2. Each disulfide bond (referenced by nomenclature SS#) is further presented with the peptide information and mass spectrometry (MS) and MSMS data obtained during the analysis in the subsequent figures and tables presented in this manuscript.

Disulfide bond SS1
A total of 30 fragments were observed, with 20 fragment ions of this peptide consistent with the linkage of Cys 10 and Cys 24 . The remaining ten fragment ions were consistent with constituent peptides (Table 3, Fig. 1).

Disulfide bond SS2
A total of 39 fragment ions of this peptide were observed with 36 fragment ions consistent with the linkage of Cys 26 and Cys 38 . Three additional fragments were consistent with constituent peptides (Table 4, Fig. 2).

Disulfide bond SS3
A total of nine fragments were observed, with six fragment ions of this peptide consistent with the linkage of Cys 45 and Cys 60 . Three fragment ions were consistent with constituent peptides (Table 5, Fig. 3).

Disulfide bond SS4
A total of 68 fragments were observed, with 45 fragment ions of this peptide consistent with the linkage of T8 to T10 through Cys 54 and Cys 72 . The remaining 23 fragments were consistent with constituent peptides (Table 6, Fig. 4).

Disulfide bonds SS5 and SS6
A total of 90 fragments were observed and four fragment ions (1/b12, 1/b13, 1/b15, and 1/b16) were consistent with an internal disulfide bond linkage between Cys 74 and Cys 85. Thirty-three fragment ions were consistent with the linkage of Cys 90 and Cys 100 . An additional 44 fragments of this

Disulfide bond SS9
A total of 35 fragment ions were observed with 25 fragment ions of this peptide consistent with the linkage of T18 to T20 through Cys 137 and Cys 148 . Ten fragments were consistent with constituent peptides (Table 9, Fig. 7).

Disulfide bonds SS10 and SS11
A total of 65 fragments were observed. Eleven fragment ions were specific to the linkage of T19 and T22, and confirmed the linkage of Cys 141 to Cys 157 . Three fragment ions were specific to the linkage between peptides T22 and T23 and confirmed the linkage of Cys 159 to Cys 172 . Thirty-two fragment ions were consistent with the linkage of T12, T14, and T16 and an additional 19 fragments were consistent with constituent peptides (Table 10, Fig. 8).

Chromatography
Digested peptides were separated with a 2695 Separations Module (Waters Corporation; Milford MA) and a 2489 UV/Vis Detector (Waters Corporation; Milford, MA) set at 214 nm. An XBridge (Waters Corporation; Milford, MA) BEH 300 C18 (2.1×250 mm, 5 µm) was used at a column temperature of 37°C and gradient with 0.1% Triflouroacetic acid (TFA) in purified water (Mobile Phase A) and 0.1% TFA in acetonitrile (Mobile Phase B) as described in [1].

Mass spectrometry
MS analysis was done with a QTOF Premier mass spectrometer (Waters Corporation; Milford, MA) equipped with an electrospray source as described in [1]. MS data was acquired in MS E mode using MassLynx v4.1 (Waters Corporation; Milford, MA). RAW MS files have been deposited in the Mass Spectrometry Interactive Virtual Environment (MassIVE) with identifier: MSV000081982.

Analysis of mass spectra
The mass spectral data was analyzed using BiopharmaLynx 1.3 (Waters Corporation; Milford, MA) as described in [1].