Title: Structures of the cGMP-dependent protein kinase in malaria parasites reveal a unique structural relay mechanism for activation

Abstract

The cyclic guanosine-3',5'-monophosphate (cGMP)-dependent protein kinase (PKG) was identified >25 y ago; however, efforts to obtain a structure of the entire PKG enzyme or catalytic domain from any species have failed. In malaria parasites, cooperative activation of PKG triggers crucial developmental transitions throughout the complex life cycle. We have determined the cGMP-free crystallographic structures of PKG from Plasmodium falciparum and Plasmodium vivax, revealing how key structural components, including an N-terminal autoinhibitory segment (AIS), four predicted cyclic nucleotide-binding domains (CNBs), and a kinase domain (KD), are arranged when the enzyme is inactive. The four CNBs and the KD are in a pentagonal configuration, with the AIS docked in the substrate site of the KD in a swapped-domain dimeric arrangement. We show that although the protein is predominantly a monomer (the dimer is unlikely to be representative of the physiological form), the binding of the AIS is necessary to keep Plasmodium PKG inactive. A major feature is a helix serving the dual role of the N-terminal helix of the KD as well as the capping helix of the neighboring CNB. A network of connecting helices between neighboring CNBs contributes to maintaining the kinase in its inactive conformation. We propose a scheme inmore » which cooperative binding of cGMP, beginning at the CNB closest to the KD, transmits conformational changes around the pentagonal molecule in a structural relay mechanism, enabling PKG to orchestrate rapid, highly regulated developmental switches in response to dynamic modulation of cGMP levels in the parasite.« less

Authors:

El Bakkouri, Majida ^[1]; Kouidmi, Imène ^[2]; Wernimont, Amy K. ^[3]; Amani, Mehrnaz ^[3]; Hutchinson, Ashley ^[3]; Loppnau, Peter ^[3]; Kim, Jeong Joo ^[4]; Flueck, Christian ^[5]; Walker, John R.  ^[3];

• Search DOE PAGES for author "Walker, John R."
• Search DOE PAGES for ORCID "0000-0002-5255-895X"

Seitova, Alma ^[3]; Senisterra, Guillermo ^[3]; Kakihara, Yoshito ^[3]; Kim, Choel ^[4]; Blackman, Michael J. ^[6]; Calmettes, Charles  ^[2];

• Search DOE PAGES for author "Calmettes, Charles"
• Search DOE PAGES for ORCID "0000-0002-2542-4382"

Baker, David A. ^[5]; Hui, Raymond  ^[7]

• Search DOE PAGES for author "Hui, Raymond"
• Search DOE PAGES for ORCID "0000-0001-5065-967X"

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+ Show Author Affiliations

1. Univ. of Toronto, ON (Canada); l’Institut National de la Recherche Scientifique (INRS) (Canada)
2. l’Institut National de la Recherche Scientifique (INRS) (Canada)
3. Univ. of Toronto, ON (Canada)
4. Baylor College of Medicine, Houston, TX (United States)
5. London School of Hygiene & Tropical Medicine (United Kingdom)
6. London School of Hygiene & Tropical Medicine (United Kingdom); Francis Crick Institute (United Kingdom)
7. Univ. of Toronto, ON (Canada); Toronto General Hospital Research Institute (Canada)

Publication Date:

Tue Jun 25 00:00:00 EDT 2019

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1558318

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Volume: 116; Journal Issue: 28; Journal ID: ISSN 0027-8424

Publisher:

National Academy of Sciences

Country of Publication:

United States

Language:

ENGLISH

Subject:

59 BASIC BIOLOGICAL SCIENCES; biological sciences; medical sciences; cyclic GMP; signal transduction; malaria; Plasmodium; structure