dc.description.abstract |
Snake venom comprises highly complex mixture of protein and peptides. Kenya is
inhabitated by many species of venomous snakes from both Viperidae and
Elapidae families. This study aimed to isolate and biochemically characterize snake
toxins from members of Viperidae (Bitis arietans) as well as Elapidae (Naja
melanoleuca, Naja ashei and Dendroaspis angusticeps) from Kilifi County. This
cross sectional study was done on venom samples extracted from eight adult snake
specimens, both male and female representing each species. Two-dimensional gel
Electrophoresis method was used to analyze the samples and later stained by silver
staining technique. Two-dimensional gels protein spots were analyzed using verified
empirical isoelectric points and molecular weights generated in comparison with the
incorporated protein standards and these data used as parameters in the protein
identification program, TagIdent. This program allowed the identification of whole
protein present in the 2D gel spot using its estimated pI, molecular masses, keywords
and species (or group of species) of interest. The estimated isoelectric points and
molecular weights data generated enabled further determination of the physical and
biochemical characteristics of the venom protein toxins identified earlier. This study
findings suggest that the venom protein toxins from Elapidae families contained very
low molecular weights of approximately 6000 daltons to 14,400 daltons, while on the
other hand, the Viperidae family had spotting at the molecular mass ranges of
14,400 daltons to 36,500 daltons. Overall, the venom toxin‘s isoelectric point ranged
from pI 4 to pI 8 and molecular mass of 7515 daltons to 13473 daltons. This study
identified the five snake venom proteins, four from Naja (Boulengrina) subfulva
formerly melanoleuca and one from Dendroaspis angusticeps in a two-dimensional gel
electrophoresis (2D) after an in-depth computer search from Swiss-Prot protein
database. They were {P00599}- Basic phospholipases A2 I, with amino acid chain
length of 1-118, pI=7.55, Mw:13473 daltons; {P00600}-Acidic phospholipases A2
DE-II, chain:1-119, pI=6.82, Mw: 13427 daltons; {P00601}–Acidic phospholipases
A2 DE-III, chain:1-119, pI=6.27, Mw: 13360 daltons); {P01383}- Long c h a i n
neurotoxin 1 with 1-71 amino acid residues, 8056 daltons, pI=8.73 and {P81030}-
Three-finger muscarinic toxin1 with 1-66 amino acids, 7518 daltons, pI=8.48. This
study finding suggests that the five identified venom protein toxins are
thermodynamically stable and highly hydrophilic molecules. However, five 2D-gel
proteins spots turned out to be negative and/or undetermined which may represent
some of the previously undescribed toxins that are yet to be deposited in protein
databases and requires further in-gel enzymatic digestion, liquid chromatography mass
spectrometry and western blot analysis to confirm their presence in the venom sample.
Therefore, further studies are needed to confirm the presence and identities of these
unknown proteins to enable better understanding of their structure―function
relationships and application as vaccine immunotherapeutic agents aiming to address
the public health problem of snakebite disabilities and improve human health in the
affected populations. |
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