Caseinolytic Proteins (Clp) in the Genus <i>Klebsiella</i>: Special Focus on ClpK
Tehrim Motiwala,
Blessing Oluebube Akumadu,
Sbahle Zuma,
Mbalenhle Sizamile Mfeka,
Wanping Chen,
Ikechukwu Achilonu,
Khajamohiddin Syed,
Thandeka Khoza
Affiliations
Tehrim Motiwala
Department of Biochemistry, School of Life Sciences, Pietermaritzburg Campus, University of Kwa-Zulu Natal, Pietermaritzburg, Scottsville 3209, South Africa
Blessing Oluebube Akumadu
Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa
Sbahle Zuma
Department of Biochemistry, School of Life Sciences, Pietermaritzburg Campus, University of Kwa-Zulu Natal, Pietermaritzburg, Scottsville 3209, South Africa
Mbalenhle Sizamile Mfeka
Department of Biochemistry, School of Life Sciences, Pietermaritzburg Campus, University of Kwa-Zulu Natal, Pietermaritzburg, Scottsville 3209, South Africa
Wanping Chen
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Ikechukwu Achilonu
Protein Structure-Function Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa
Khajamohiddin Syed
Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa
Thandeka Khoza
Department of Biochemistry, School of Life Sciences, Pietermaritzburg Campus, University of Kwa-Zulu Natal, Pietermaritzburg, Scottsville 3209, South Africa
Caseinolytic proteins (Clp), which are present in both prokaryotes and eukaryotes, play a major role in cell protein quality control and survival of bacteria in harsh environmental conditions. Recently, a member of this protein family, ClpK was identified in a pathogenic strain of Klebsiella pneumoniae which was responsible for nosocomial infections. ClpK is linked to the thermal stress survival of this pathogen. The genome wide analysis of Clp proteins in Klebsiella spp. indicates that ClpK is present in only 34% of the investigated strains. This suggests that the uptake of the clpk gene is selective and may only be taken up by a pathogen that needs to survive harsh environmental conditions. In silico analyses and molecular dynamic simulations show that ClpK is mainly α-helical and is highly dynamic. ClpK was successfully expressed and purified to homogeneity using affinity and anion exchange chromatography. Biophysical characterization of ClpK showed that it is predominantly alpha-helical, and this is in agreement with in silico analysis of the protein structure. Furthermore, the purified protein is biologically active and hydrolyses ATP in a concentration- dependent manner.
