title: Crystal structures of the carboxyl cGMP binding domain of the Plasmodium falciparum cGMP-dependent protein kinase reveal a novel capping triad crucial for merozoite egress.
abstract: The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is a key regulator across the malaria parasite life cycle. Little is known about PfPKG's activation mechanism. Here we report that the carboxyl cyclic nucleotide binding domain functions as a "gatekeeper" for activation by providing the highest cGMP affinity and selectivity. To understand the mechanism, we have solved its crystal structures with and without cGMP at 2.0 and 1.9 Å, respectively. These structures revealed a PfPKG-specific capping triad that forms upon cGMP binding, and disrupting the triad reduces kinase activity by 90%. Furthermore, mutating these residues in the parasite prevents blood stage merozoite egress, confirming the essential nature of the triad in the parasite. We propose a mechanism of activation where cGMP binding allosterically triggers the conformational change at the αC-helix, which bridges the regulatory and catalytic domains, causing the capping triad to form and stabilize the active conformation.
authors: Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America; Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany.
authors: Jeong Joo
authors: JJ
authors: Kim
authors: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors: Christian
authors: C
authors: Flueck
authors: Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany.
authors: Eugen
authors: E
authors: Franz
authors: Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America.
authors: Eduardo
authors: E
authors: Sanabria-Figueroa
authors: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors: Eloise
authors: E
authors: Thompson
authors: Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany.
authors: Robin
authors: R
authors: Lorenz
authors: Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany.
authors: Daniela
authors: D
authors: Bertinetti
authors: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors: David A
authors: DA
authors: Baker
authors: Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany.
authors: Friedrich W
authors: FW
authors: Herberg
authors: Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America.
authors: Choel
authors: C
authors: Kim
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D015151:Immunoblotting; D008018:Life Cycle Stages / Q000502:physiology*; D052940:Merozoites / Q000502:physiology*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000378:metabolism*; D014162:Transfection
chemical_list: D015800:Protozoan Proteins; D017869:Cyclic GMP-Dependent Protein Kinases
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