title: The gatekeeper residue and beyond: homologous calcium-dependent protein kinases as drug development targets for veterinarian Apicomplexa parasites.
abstract: Specific roles of individual CDPKs vary, but in general they mediate essential biological functions necessary for parasite survival. A comparative analysis of the structure-activity relationships (SAR) of Neospora caninum, Eimeria tenella and Babesia bovis calcium-dependent protein kinases (CDPKs) together with those of Plasmodium falciparum, Cryptosporidium parvum and Toxoplasma gondii was performed by screening against 333 bumped kinase inhibitors (BKIs). Structural modelling and experimental data revealed that residues other than the gatekeeper influence compound-protein interactions resulting in distinct sensitivity profiles. We subsequently defined potential amino-acid structural influences within the ATP-binding cavity for each orthologue necessary for consideration in the development of broad-spectrum apicomplexan CDPK inhibitors. Although the BKI library was developed for specific inhibition of glycine gatekeeper CDPKs combined with low inhibition of threonine gatekeeper human SRC kinase, some library compounds exhibit activity against serine- or threonine-containing CDPKs. Divergent BKI sensitivity of CDPK homologues could be explained on the basis of differences in the size and orientation of the hydrophobic pocket and specific variation at other amino-acid positions within the ATP-binding cavity. In particular, BbCDPK4 and PfCDPK1 are sensitive to a larger fraction of compounds than EtCDPK1 despite the presence of a threonine gatekeeper in all three CDPKs.
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Katelyn R
authors.initials: KR
authors.lastname: Keyloun
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Molly C
authors.initials: MC
authors.lastname: Reid
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Choi
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Song
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Anna M W
authors.initials: AMW
authors.lastname: Fox
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Heidi K
authors.initials: HK
authors.lastname: Hillesland
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: Zhongsheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: RamaSubbaRao
authors.initials: R
authors.lastname: Vidadala
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: Ethan A
authors.initials: EA
authors.lastname: Merritt
authors.affiliation: Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA.
authors.forename: Audrey O T
authors.initials: AOT
authors.lastname: Lau
authors.affiliation: Department of Chemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: Dustin J
authors.initials: DJ
authors.lastname: Maly
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Seattle, USA.
authors.forename: Erkang
authors.initials: E
authors.lastname: Fan
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Lynn K
authors.initials: LK
authors.lastname: Barrett
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Wesley C
authors.initials: WC
authors.lastname: Van Voorhis
authors.affiliation: Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Seattle, USA.
authors.forename: Kayode K
authors.initials: KK
authors.lastname: Ojo
mesh_terms: D000818:Animals; D016782:Apicomplexa / Q000201:enzymology* / Q000235:genetics; D016793:Babesia bovis / Q000201:enzymology / Q000235:genetics; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D016786:Eimeria tenella / Q000201:enzymology / Q000235:genetics; D005523:Food Supply; D006801:Humans; D008958:Models, Molecular; D018688:Neospora / Q000201:enzymology / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D011528:Protozoan Infections / Q000188:drug therapy / Q000469:parasitology*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D054852:Small Molecule Libraries; D013329:Structure-Activity Relationship; D014730:Veterinary Medicine; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D015800:Protozoan Proteins; D054852:Small Molecule Libraries; D017871:Calcium-Calmodulin-Dependent Protein Kinases