Academic article

Isolation of constitutive variants of a subfamily 10 histidine protein kinase (SppK) from Lactobacillus using random mutagenesis

Mathiesen, Geir; Axelsen, Gunnhild W.; Eijsink, Vincent; Axelsson, Lars

Publication details

Journal: Archives of Microbiology, vol. 184, p. 327–334, 2006

Publisher: Springer

International Standard Numbers:
Printed: 0302-8933
Electronic: 1432-072X

Open Access: none


The histidine protein kinase SppK is a peptide
pheromone-activated kinase that regulates the production
of the bacteriocin sakacin P in Lactobacillus sakei.
SppK belongs to subfamily 10 of histidine protein kinases
(HPKs), which regulate important processes in
Gram-positive bacteria, including virulence, competence
and bacteriocin production. To obtain insight into the
functional properties of this relatively unknown class of
HPKs, we have subjected SppK to random mutagenesis
by error-prone PCR, followed by selection for mutants
displaying a constitutive phenotype. Most identified
mutations were clustered in a predicted coiled coil-like
region, which is an important part of the HPK dimer
interface and which includes the autophosphorylated
histidine. Other mutations were located in the junctions
between the dimerization domain and the membrane
receptor domain or the catalytic kinase domain. Interestingly,
two previously identified constitutive variants
of ComD, an SppK homologue involved in competence
regulation in Streptococcus pneumoniae, contained single
mutations in the same regions.