PARENT SESSION
Posters P4Aa Chlorophyll and bilin based antenna systems. Abstracts (239-271)

Phylogeny of the light-harvesting antennae in oxygenic photosynthetic organisms. Yinan Zhang^*,1, Lars Jermiin¹, Anthony Larkum¹, ¹ School of biological sciences, Unviersity of Sydney, Sydney, NSW, Australia

ABSTRACT- The evolution of the inner antenna complexes of photosystems in green plants cyanobacteria and photosynthetic bacteria, and of the peripheral isiA and pcb antennna complexes, were analyzed using phylogenetic methods. Amino acids were aligned using Clustal W and subsequently refined to accommodate the positions of the six membranes-spanning helices. Phylogenetic analysis was carried out on the helices alone and on the whole sequence by using distance-based, maximum-likelihood, and Bayesian methods. Rates variation among sites was modeled using a discrete gamma distribution. Whole sequences gave a variety of trees that generally indicated that CP43, isiA and pcb grouped together. Using only the membrane spanning helices a consistent topology was inferred, indicating the antennae peptide in photosynthetic bacteria was the first lineage to diverge from the other lineages, and that the isiA and pcb peptides diverged most recently from a CP43 lineage (the outgroup was identified through mid-point rooting of trees inferred by the distance and maximum likelihood methods).

KEY WORDS: antenna, phylogenetic, helix, tree