Dataset Information

Crystal structure of the coxsackievirus A16 RNA-dependent RNA polymerase elongation complex reveals novel features in motif A dynamics.

ABSTRACT: The RNA-dependent RNA polymerases (RdRPs) encoded by RNA viruses represent a unique class of nucleic acid polymerases. Unlike other classes of single-subunit polymerases, viral RdRPs have evolved a unique conformational change in their palm domain to close the active site during catalysis. The hallmark of this conformational change is the backbone shift of the polymerase motif A from an "open" state to a "closed" state, allowing two universally conserved aspartic acid residues to orient toward each other for divalent metal binding and catalysis. The "closed" motif A conformation was only observed upon the binding of correct NTP in RdRP catalytic complexes or under rare conditions such as induced by a bound lutetium ion or a bound glutamate molecule. By solving the crystal structure of the catalytic elongation complex of the coxsackievirus RdRP, we in this work observed for the first time the "closed" motif A conformation in the absence of an NTP substrate or other conformational-change-inducing factors. This observation emphasizes the intrinsic dynamic features of viral RdRP motif A, and solidifies the structural basis for how this important structural element participates in catalytic events of the RdRPs.

SUBMITTER: Bi P

PROVIDER: S-EPMC6598878 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Crystal structure of the coxsackievirus A16 RNA-dependent RNA polymerase elongation complex reveals novel features in motif A dynamics.

Bi Peng P Shu Bo B Gong Peng P

Virologica Sinica 20171201 6

The RNA-dependent RNA polymerases (RdRPs) encoded by RNA viruses represent a unique class of nucleic acid polymerases. Unlike other classes of single-subunit polymerases, viral RdRPs have evolved a unique conformational change in their palm domain to close the active site during catalysis. The hallmark of this conformational change is the backbone shift of the polymerase motif A from an "open" state to a "closed" state, allowing two universally conserved aspartic acid residues to orient toward e ...[more]

PMID: 29164396

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Project description:RNA-dependent RNA polymerases play a vital role in the growth of RNA viruses where they are responsible for genome replication, but do so with rather low fidelity that allows for the rapid adaptation to different host cell environments. These polymerases are also a target for antiviral drug development. However, both drug discovery efforts and our understanding of fidelity determinants have been hampered by a lack of detailed structural information about functional polymerase-RNA complexes and the structural changes that take place during the elongation cycle. Many of the molecular details associated with nucleotide selection and catalysis were revealed in our recent structure of the poliovirus polymerase-RNA complex solved by first purifying and then crystallizing stalled elongation complexes. In the work presented here we extend that basic methodology to determine nine new structures of poliovirus, coxsackievirus, and rhinovirus elongation complexes at 2.2-2.9 Å resolution. The structures highlight conserved features of picornaviral polymerases and the interactions they make with the template and product RNA strands, including a tight grip on eight basepairs of the nascent duplex, a fully pre-positioned templating nucleotide, and a conserved binding pocket for the +2 position template strand base. At the active site we see a pre-bound magnesium ion and there is conservation of a non-standard backbone conformation of the template strand in an interaction that may aid in triggering RNA translocation via contact with the conserved polymerase motif B. Moreover, by engineering plasticity into RNA-RNA contacts, we obtain crystal forms that are capable of multiple rounds of in-crystal catalysis and RNA translocation. Together, the data demonstrate that engineering flexible RNA contacts to promote crystal lattice formation is a versatile platform that can be used to solve the structures of viral RdRP elongation complexes and their catalytic cycle intermediates.

Project description:Background: Hand, Foot and Mouth Disease (HFMD) is a major public health concern in the Asia-Pacific region. Most recent HFMD outbreaks have been caused by enterovirus A71 (EV-A71), coxsackievirus A16 (CVA16), CVA10, and CVA6. There has been no report regarding the epidemiology and genetic diversity of CVA16 in Vietnam. Such knowledge is critical to inform the development of intervention strategies. Materials and Methods: From 2011 to 2017, clinical samples were collected from in- and outpatients enrolled in a HFMD research program conducted at three referral hospitals in Ho Chi Minh City (HCMC), Vietnam. Throat or rectal swabs positive for CVA16 with sufficient viral load were selected for whole genome sequencing and evolutionary analysis. Results: Throughout the study period, 320 CVA16 positive samples were collected from 2808 HFMD patients (11.4%). 59.4% of patients were male. The median age was 20.8 months (IQR, 14.96-31.41). Patients resided in HCMC (55.3%), Mekong Delta (22.2%), and South East Vietnam (22.5%). 10% of CVA16 infected patients had moderately severe or severe HFMD. CVA16 positive samples from 153 patients were selected for whole genome sequencing, and 66 complete genomes were obtained. Phylogenetic analysis demonstrated that Vietnamese CVA16 strains belong to a single genogroup B1a that clusters together with isolates from China, Japan, Thailand, Malaysia, France and Australia. The CVA16 strains of the present study were circulating in Vietnam some 4 years prior to its detection in HFMD cases. Conclusion: We report for the first time on the molecular epidemiology of CVA16 in Vietnam. Unlike EV-A71, which showed frequent replacement between subgenogroups B5 and C4 every 2-3 years in Vietnam, CVA16 displays a less pronounced genetic alternation with only subgenogroup B1a circulating in Vietnam since 2011. Our collective findings emphasize the importance of active surveillance for viral circulation in HFMD endemic countries, critical to informing outbreak response and vaccine development.

Dataset Information

Crystal structure of the coxsackievirus A16 RNA-dependent RNA polymerase elongation complex reveals novel features in motif A dynamics.

Publications

Crystal structure of the coxsackievirus A16 RNA-dependent RNA polymerase elongation complex reveals novel features in motif A dynamics.

Similar Datasets

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