Phylogenetic relationships of NRPS A-domains specific for L-proline or its derivatives.

<p>A rooted, neighbor-joining phylogenetic tree was constructed based on the full length amino acid sequences of stand-alone A-domains and excised sequences of modular A-domains. Bootstrap values (100 replicates) above 50% are indicated at the nodes. Modular A-domains are represented by name of respective NRPS module and marked with a ■, stand-alone A-domains are marked with a ▲. The substrates for each domain include L-proline (Pro), L-proline derivatives with one carbon side chains (Pro1C), L-proline derivatives with two carbon side chains (Pro2C), and L-proline derivatives with three carbon side chain (Pro3C). Those A-domains specific for Pro2C or Pro3C substrates are highlighted. Number in parentheses behind the name of respective NRPS denotes the number of the module in NRPS protein chain, if relevant; letter in parentheses denotes the source organism. The GenBank accession numbers, producing strains, and references describing each A-domain are listed. Percent sequence identities with LmbC and CcbC were calculated from pairwise alignments. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084902#pone.0084902.s002" target="_blank">Figure S1A</a> shows an identical phylogenetic tree reflecting phylogenetic distances, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084902#pone.0084902.s002" target="_blank">Figure S1B</a> shows the identical set analysis using maximum likelihood method.