Molecular evolution of group II phospholipases A2

Abstract

The nucleotide sequences of 13 cDNAs encoding group II phospholipases A2 (PLA2s), which are from viperidae snake venoms and from mammalian sources, were aligned and analyzed by phylogenetic trees constructed using various components of the sequences. The evolutionary trees derived from the combined sequences of the untranslated (5' and 3') region and the signal peptide region of cDNAs were in accord with the consequences from taxonomy. In contrast, the evolutionary trees from the mature protein-coding region sequences of cDNAs and from the amino acid sequences showed random patterns. These observations indicated that the mature protein-coding region has evolved through a process differently from the untranslated and signal peptide regions. The trees built from the nucleotide differences at each of three positions of codons in the mature protein-coding region suggested that snake-venom-gland PLA2 genes have evolved via a process different from mammalian PLA2 genes. The occurrence of accelerated evolution has been recently discovered in Trimeresurus flavoviridis venom-gland group II PLA2 isozyme genes (Nakashima et al. 1993, Proc Natl Acad Sci USA 90:5964-5968), so the present phylogenetic analysis together with the estimation of nucleotide divergence of cDNAs provides further evidence that snake-venom-group II PLA2 isozyme genes have evolved by accelerated evolution to gain diverse physiological activities.

Snake Venomics of the Lancehead Pitviper Bothrops asper: Geographic, Individual, and Ontogenetic Variations

“…Thus, except for these proteins, all of which were found in the pooled venoms (Table 2), the peptide mass fingerprinting approach alone was unable to identify any protein in the databases. In addition, as expected from the rapid amino acid sequence divergence of venom proteins evolving under accelerated evolution, [50][51][52][53][54][55][56] with a few exceptions, the product ion spectra did not match any known protein. Hence, mass spectra were manually interpreted for de novo sequencing and the CID-MS/ MS-deduced peptide ion sequences (Table 2) were submitted to BLAST similarity searches.…”

Genomic organization of the KTX2 gene, encoding a ‘short’ scorpion toxin active on K+ channels

“…In contrast, in the nucleotide sequences of genes and cDNAs encoding the phospholipases A2 found in snake venoms [16], the protein-coding regions are much more variable than the untranslated regions, including introns, which are highly conserved (> 79%).…”

Weighting and Congruence: A Case Study Based on Three Mitochondrial Genes in Pitvipers

“…Given the presumed Upper Cretaceous origin and the high specialization of pitvipers, it is interesting to notice that phylogenetic relationships within this subfamily have been particularly difficult to assess whatever the kind of characters used. So, classical morphological characters as configuration of head shields have proven to be highly homoplastic (Kraus et al, 1996), venom components as group II PLA2 are encoded by genes having undergone accelerated evolution (Ogawa et al, 1995), and various behavioral and ecological patterns such as viviparity, arboreality, or open-mouth threat displays have each been found in most of the pitviper lineages (Greene, 1992(Greene, , 1994.…”