Polypeptide p41 of a Norwalk-Like Virus Is a Nucleic Acid-Independent Nucleoside Triphosphatase

Pfister, Thomas D.; Wimmer, Eckard

doi:10.1128/jvi.75.4.1611-1619.2001

Cited by 70 publications

(73 citation statements)

References 67 publications

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“…The NoV genome is 7.3-7.7 kb long and includes 3 open reading frames (ORF) that encode a non-structural polyprotein, a major capsid protein (VP1 or capsid protein), and a minor capsid protein (VP2 or small basic protein). The polyprotein undergoes protease processing to produce several nonstructural proteins [1,39,40]. The capsid protein is composed of a conserved shell (S) domain and hypervariable protruding (P) domain, with the latter subdivided into P1A, P2 and P1B subdomains based on x-ray crystallography of Norwalk virus VLPs [27].…”

Section: Genetic Organization and Classification Of Novs And Savsmentioning

confidence: 99%

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Wang

Costantini

Saif

2007

Vaccine

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Porcine enteric caliciviruses include sapoviruses and noroviruses. Porcine sapoviruses infect pigs of all ages and cause diarrhea in young pigs, whereas porcine noroviruses were detected exclusively from adult pigs without clinical signs. Importantly, certain porcine norovirus strains were genetically and antigenically related to human noroviruses. This raises public health concerns that pigs may be reservoirs for emergence of epidemic human norovirus strains. This article reviews the discovery of porcine noroviruses and sapoviruses, their classification, diagnosis, epidemiology and genetic and antigenic relatedness to human caliciviruses.

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Section: Genetic Organization and Classification Of Novs And Savsmentioning

confidence: 99%

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Wang

Costantini

Saif

2007

Vaccine

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“…RNA viruses that infect both plants (families Comoviridae and Sequiviridae) and animals (families Picornaviridae and Caliciviridae) have been predicted to encode SF3 helicases but none of the proteins have been shown to unwind duplex RNA. Nevertheless, the poliovirus 2C protein [106,107], the polio-like virus echovirus 9 strain barty NS protein 2C [108,109], and a Norwalk-like virus 2c-like protein, called p41 [110] have the abilities to hydrolyze NTPs. Perhaps the conserved motor function in these proteins is used for something other than RNA unwinding.…”

Section: Human Papillomaviruses Helicasementioning

confidence: 99%

Understanding Helicases as a Means of Virus Control

Frick¹,

Lam²

2006

CPD

103

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Helicases are promising antiviral drug targets because their enzymatic activities are essential for viral genome replication, transcription, and translation. Numerous potent inhibitors of helicases encoded by herpes simplex virus, severe acute respiratory syndrome coronavirus, hepatitis C virus, Japanese encephalitis virus, West Nile virus, and human papillomavirus have been recently reported in the scientific literature. Some inhibitors have also been shown to decrease viral replication in cell culture and animal models. This review discusses recent progress in understanding the structure and function of viral helicases to help clarify how these potential antiviral compounds function and to facilitate the design of better inhibitors. The above helicases and all related viral proteins are classified here based on their evolutionary and functional similarities, and the key mechanistic features of each group are noted. All helicases share a common motor function fueled by ATP hydrolysis, but differ in exactly how the motor moves the protein and its cargo on a nucleic acid chain. The helicase inhibitors discussed here influence rates of helicase-catalyzed DNA (or RNA) unwinding by preventing ATP hydrolysis, nucleic acid binding, nucleic acid release, or by disrupting the interaction of a helicase with a required cofactor.

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“…ORF1 encodes a large polyprotein (nonstructural protein), which is processed by the viral protease into six proteins, including putative 2C-like RNA helicase (with NTPase activity, but not RNA helicase activity, proven [35]), 3B VPg, 3C-like protease, and 3D RNA-dependent RNA polymerase. ORF2 encodes a capsid protein (structural protein), and 180 molecules of the protein are organized into a native NLV virion (36).…”

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confidence: 99%

Identification of Active-Site Amino Acid Residues in the Chiba Virus 3C-Like Protease

Someya

Takeda

Miyamura

2002

J Virol

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The 3C-like protease of the Chiba virus, a Norwalk-like virus, is one of the chymotrypsin-like proteases. To identify active-site amino acid residues in this protease, 37 charged amino acid residues and a putative nucleophile, Cys139, within the GDCG sequence were individually replaced with Ala in the 3BC precursor, followed by expression in Escherichia coli, where the active 3C-like protease would cleave 3BC into 3B (VPg) and 3C (protease). Among 38 Ala mutants, 7 mutants (R8A, H30A, K88A, R89A, D138A, C139A, and H157A) completely or nearly completely lost the proteolytic activity. Cys139 was replaceable only with Ser, suggesting that an SH or OH group in the less bulky side chain was required for the side chain of the residue at position 139. His30, Arg89, and Asp138 could not be replaced with any other amino acids. Although Arg8 was also not replaceable for the 3B/3C cleavage and the 3C/3D cleavage, the N-terminal truncated mutant devoid of Arg8 significantly cleaved 3CD into 3C and 3D (polymerase), indicating that Arg8 itself was not directly involved in the proteolytic cleavage. As for position 88, a positively charged residue was required because the Arg mutant showed significant activity. As deduced by the X-ray structure of the hepatitis A virus 3C protease, Arg8, Lys88, and Arg89 are far away from the active site, and the side chain of Asp138 is directed away from the active site. Therefore, these are not catalytic residues. On the other hand, all of the mutants of His157 in the S1 specificity pocket tended to retain very slight activity, suggesting a decreased level of substrate recognition. These results, together with a sequence alignment with the picornavirus 3C proteases, indicate that His30 and Cys139 are active-site residues, forming a catalytic dyad without a carboxylate directly participating in the proteolysis.

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Polypeptide p41 of a Norwalk-Like Virus Is a Nucleic Acid-Independent Nucleoside Triphosphatase

Cited by 70 publications

References 67 publications

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Porcine enteric caliciviruses: Genetic and antigenic relatedness to human caliciviruses, diagnosis and epidemiology

Understanding Helicases as a Means of Virus Control

Identification of Active-Site Amino Acid Residues in the Chiba Virus 3C-Like Protease

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