Deep mining of the venom of the red-headed krait Bungarus flaviceps by a proteomic approach Chapeaurouge, A.1, Silva, A.1, Carvalho, P.C.2, McCleary, R.3, Perales, J.1, Kini, M.R.3, Mackessy, St.4 1Fundação Oswaldo Cruz, Laboratório de Toxinologia, Rio de Janeiro, Brasil, 2Carlos Chagas Institute, Laboratory for Proteomics and Protein Engineering, Parana, Brasil, 3National University of Singapore, Department of Biological Sciences, Singapore, 4University of Northern Colorado, School of Biological Sciences, Colorado, USA Introduction: Snake venoms are rich sources of biologically active peptides and proteins.Bungarus flaviceps, also known as the red-headed krait, is an elapid snake encountered in Southeast Asia primarily in mountainous regions from the north of Myanmar to the south of Indonesia. To date, the venom proteome of this snake has only been analyzed at the transcriptome level. In order to get a more detailed view of this particular venom we embarked upon a study of the venom proteome. Objective: To investigate the venom of the elapid snake Bungarus flaviceps by a proteomic approach. Materials and methods: Lyophilized venom was initially trypsinized and chromatographically separated tryptic peptides were analyzed on a MALDI 5800 Tof-Tof (ABSciex) instrument as well as on an electrospray Q ExactiveTM orbitrap (Thermo) mass spectrometer. Discussion and results: In the present study we have investigated the proteome of the venom of B. flaviceps by a complementary approach of electrospray and MALDI mass spectrometry to reach a profound understanding of even minor venom compounds. The mass spectrometric data were analyzed by automated searches against a snake venom database as well as by de novo sequencing of the tandem mass spectra followed by BLAST analysis. These investigations revealed the presence of 18 snake venom protein families as evidenced by the detection of the corresponding peptides. This is of particular interest in the light of a recent transcriptome analysis of the B. flaviceps venom, which identified six different snake venom protein families and supports the view that transcriptomics and proteomics analysis of snake venoms are highly complementary. Conclusion: The present proteome analysis revealed 12 additional toxin families as compared to the corresponding transcriptome study, which might indicate that Bungarus venoms are more complex and diversified than initially appreciated. This study might aid in the treatment of krait envenomation as well as in the understanding of snake venom molecular evolution. Keywords: Bungarus flaviceps, proteomics, snake venom Funding agencies: FAPERJ, CNPq, and PDTIS .