Extreme convergent evolution in defensin proteins & quantitative maps of their sequence space
2020-03-01T08:37:58Z (GMT) by
Poster presented at
Gordon AMPs 2017
Defensins are small, charged, disulphide-rich
eukaryotic proteins with diverse sequences, structures, and
functions. Their antimicrobial activities are of particular interest
for protecting crops and humans from pathogens.
They have been traditionally treated as a single superfamily.
However, we present evidence that there exist two independent
evolutionary origins of defensins, based on their secondary
structure element order, disulphide topology, and tertiary
structures. These two superfamilies, the cis-defensins and transdefensins,
exhibit some of the most extensive convergent
evolution of protein sequence, structure and function.
We have developed new methods of sequence alignment and
analysis to overcome the difficulties of investigating such short
and divergent sequences. Multivariate analysis of protein
sequence space allows grouping of defensins into naturally
occurring clusters which describe the residue properties that
separate phyla and functions. It can be further used to design
synthetic, cluster-central, archetypal defensin sequences.