Proteomic analysis of the venom from the scorpion Mesobuthus martensii

The scorpion Mesobuthus martensii is the most populous species in eastern Asian countries, and several toxic components have been identified from their venoms. Nevertheless, a complete proteomic profile of the venom of M. martensii is still not available. In this study, the venom of M. martensii was analyzed by comprehensive proteomic approaches. 153 fractions were isolated from the M. martensii venom by 2-DE, SDS-PAGE and RP-HPLC. The ESI-Q-TOF MS results of all fractions were used to search the scorpion genomic and transcriptomic databases. Totally, 227 non-redundant protein sequences were unambiguously identified, composed of 134 previously known and 93 previously unknown proteins. Among 134 previously known proteins, 115 proteins were firstly confirmed from the M. martensii crude venom and 19 toxins were confirmed once again, involving 43 typical toxins, 7 atypical toxins, 12 venom enzymes and 72 cell associated proteins. In typical toxins, 7 novel-toxin sequences were identified, including 3 Na(+)-channel toxins, 3K(+)-channel toxins and 1 no-annotation toxin. These results increased 230% (115/50) venom components compared with previous studies from the M. martensii venom, especially 50% (24/48) typical toxins. Additionally, a mass fingerprint obtained by MALDI-TOF MS indicated that the scorpion venom contained more than 200 different molecular mass components.

This work firstly gave a systematic investigation of the M. martensii venom by combined proteomics strategy coupled with genomics and transcriptomics. A large number of protein components were unambiguously identified from the venom of M. martensii, most of which were confirmed for the first time. We also contributed 7 novel-toxin sequences and 93 protein sequences previously unknown to be part of the venom, for which we assigned potential biological functions. Besides, we obtained a mass fingerprint of the M. martensii venom. Together, our study not only provides the most comprehensive catalog of the molecular diversity of the M. martensii venom at the proteomic level, but also enriches the composition information of scorpion venom.