Biology and Earth Science Faculty Scholarship

Document Type


Publication Date


Publication Title

Journal of Bacteriology


ASM Journals


Cyclic Dimeric GMP, Gram-Negative Bacteria, Gram-Positive Bacteria, Phosphodiesterases, Streptomyces Coelicolor, Transposon Mutation, Morphology, RmdA, RmdB


Cyclic dimeric GMP (c-di-GMP) regulates numerous processes in Gram-negative bacteria, yet little is known about its role in Gram-positive bacteria. Here we characterize two c-di-GMP phosphodiesterases from the filamentous high-GC Gram-positive actinobacterium Streptomyces coelicolor, involved in controlling colony morphology and development. A transposon mutation in one of the two phosphodiesterase genes, SCO0928, hereby designated rmdA (regulator ofmorphology and development A), resulted in decreased levels of spore-specific gray pigment and a delay in spore formation. The RmdA protein contains GGDEF-EAL domains arranged in tandem and possesses c-di-GMP phosphodiesterase activity, as is evident from in vitro enzymatic assays using the purified protein. RmdA contains a PAS9 domain and is a hemoprotein. Inactivation of another GGDEF-EAL-encoding gene, SCO5495, designated rmdB, resulted in a phenotype identical to that of the rmdA mutant. Purified soluble fragment of RmdB devoid of transmembrane domains also possesses c-di-GMP phosphodiesterase activity. ThermdA rmdB double mutant has a bald phenotype and is impaired in aerial mycelium formation. This suggests that RmdA and RmdB functions are additive and at least partially overlapping. The rmdA and rmdB mutations likely result in increased local pools of intracellular c-di-GMP, because intracellular c-di-GMP levels in the single mutants did not differ significantly from those of the wild type, whereas in the double rmdA rmdB mutant, c-di-GMP levels were 3-fold higher than those in the wild type. This study highlights the importance of c-di-GMP-dependent signaling in actinomycete colony morphology and development and identifies two c-di-GMP phosphodiesterases controlling these processes.

First Page


Last Page







T.D.H. and M.-H.R. contributed equally to this publication and should be considered co-first authors.

Otterbein Student: Robert M. Gelger

Original Citation

Hull, TD, Ryu, MH, Sullivan, MJ, Johnson, RC, Klena, NT, Gieger, RM, Gomelsky, M and Bennett, JA. 2012. Cyclic DI-GMP Phosphodiesterases RmdA and RmdB are involved in regulating colony morphology and development in Streptomyces coelicolor. Journal of Bacteriology 194(17):4642 – 4651.




Publisher's Version

Publisher's Statement

Peer Reviewed




To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.