Structural and functional studies of Arabidopsis thaliana triphosphate tunnel metalloenzymes reveal roles for additional domains

Article Article scientifique Article Structural and functional studies of Arabidopsis thaliana triphosphate tunnel metalloenzymes reveal roles for additional domains eng 2022-08-30 2022-11 author Pesquera-Alonso Marta Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 811457 author Martinez Font Jacobo Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 828584 author Maillot Benoît Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 915216 Département des sciences végétales (BIVEG) author Wang Kai 0000-0001-8592-0970 Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 938134 Département des sciences végétales (BIVEG) author Hofmann Manuel Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 813220 author Raia Pierre 0000-0003-3469-1922 Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 930734 Département des sciences végétales (BIVEG) author Loubery Sylvain Philippe 0000-0001-7061-9456 Plant Imaging Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 669207 Département des sciences végétales (BIVEG) author Steensma Priscille 0000-0002-3628-2228 Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. 846338 author Hothorn Michael Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. Electronic address: michael.hothorn@unige.ch. 826130 Département des sciences végétales (BIVEG) author Fitzpatrick Thérésa Bridget Vitamins & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. Electronic address: theresa.fitzpatrick@unige.ch. 684438 Département des sciences végétales (BIVEG) 102438 10.1016/j.jbc.2022.102438 36049521 0021-9258 PMC9582702 Triphosphate tunnel metalloenzymes (TTMs) are found in all biological kingdoms and have been characterized in microorganisms and animals. Members of the TTM family have divergent biological functions and act on a range of triphosphorylated substrates (RNA, thiamine triphosphate, and inorganic polyphosphate). TTMs in plants have received considerably less attention and are unique in that some homologs harbor additional domains including a P-loop kinase and transmembrane domain. Here, we report on structural and functional aspects of the multimodular TTM1 and TTM2 of Arabidopsis thaliana. Our tissue and cellular microscopy studies show that both AtTTM1 and AtTTM2 are expressed in actively dividing (meristem) tissue and are tail-anchored proteins at the outer mitochondrial membrane, mediated by the single C-terminal transmembrane domain, supporting earlier studies. In addition, we reveal from crystal structures of AtTTM1 in the presence and absence of a nonhydrolyzable ATP analog a catalytically incompetent TTM tunnel domain tightly interacting with the P-loop kinase domain that is locked in an inactive conformation. Our structural comparison indicates that a helical hairpin may facilitate movement of the TTM domain, thereby activating the kinase. Furthermore, we conducted genetic studies to show that AtTTM2 is important for the developmental transition from the vegetative to the reproductive phase in Arabidopsis, whereas its closest paralog AtTTM1 is not. We demonstrate through rational design of mutations based on the 3D structure that both the P-loop kinase and TTM tunnel modules of AtTTM2 are required for the developmental switch. Together, our results provide insight into the structure and function of plant TTM domains. Arabidopsis X-ray crystallography Development Mitochondria Triphosphate tunnel metalloenzyme Uridine/cytidine kinase Animals Arabidopsis / metabolism Arabidopsis Proteins / metabolism Polyphosphates Metalloproteins / chemistry Acid Anhydride Hydrolases / metabolism Dewey 580 Swiss National Science Foundation Unraveling the molecular mechanisms and regulatory networks controlling responses to thiamin (vitamin B1) or pyridoxine (vitamin B6) in Arabidopsis. 141117 CH Projects Swiss National Science Foundation Dissecting the role of vitamin B1 derivatives and the interaction between vitamin B1 homeostasis and the circadian clock. 162555 CH Projects European Commission Identity and functions of polyphosphate polymerases in eukaryotes 310856 EUROPOLYPS EU FP7 45 Département des sciences végétales 163 false 830 Groupe Hothorn 829 Groupe Fitzpatrick The Journal of biological chemistry 298 11 418189ea-893e-4416-890c-70ddb543cffa Article (Published version) Public Article-scientifique-from-europePmc.pdf 4194174 application/pdf CC BY-NC-ND 03fc840c889b987aa308e4cd3c5e7a5db860c6cf77d9913629d12c75416d117a ee53d639-14b6-40b6-89fa-e53878e3b06d Appendix Public mmc1.pdf 6433693 application/pdf d34f012383fc1313627692dcb8fc8b173829a347533574e687a505cec5df69d7 openAccess Faculté des sciences / Section de biologie / Département des sciences végétales

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Structural and functional studies of Arabidopsis thaliana triphosphate tunnel metalloenzymes reveal roles for additional domains	The Journal of biological chemistry			2022	587	778

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