系统发生学与进化生物学杂志

The Distribution of Polyhedral Bacterial Microcompartments Suggests Frequent Horizontal Transfer and Operon Reassembly

Abstract

Farah Abdul-Rahman, Elsa Petit and Jeffrey L Blanchard

Bacterial microcompartments (BMCs) are proteinaceous organelles that carry out specific metabolic reactions. Using domain representations of the BMC shell proteins, we identified BMCs in genomes of 358 bacterial species including human gut microbes, bioremediation agents, cellulosic ethanol producers, and pathogens. Multiple BMCs of different metabolic types are present in 40% of the BMC-containing genomes. BMC genes frequently clustered at a single locus that includes enzymes related to the compartment’s metabolic function. The distribution of BMC-containin species was mapped onto a phylogenetic tree constructed from 16S rRNA sequences. The presence of BMCs was sporadically distributed across the phylogenetic tree. All bacterial families that contained species with BMCs also had species without them. Even within a species, BMC number varied, indicative of frequent horizontal transfer and gene loss. Similarly, phylogenetic trees constructed from individual BMC genes indicated that horizontal gene transfer of the BMC loci is a common occurrence.