Index >> Virus Structure and Classification >> Virion Enzymes

Enzyme

Enzymes affecting interaction of host cell surface with virions

Neuraminidase.
Endoglycosidase.
Fusion factor.

Ortho - and paramyxovirus.

E. coli phages. Paramyxovirus.

DNA- mRNA transcription enzymes

DNA-dependent RNA polymerase.
dsRNA transcriptase
.

ssRNA transcriptase.

Transcribes ss mRNA.

Transcribes ss mRNA.

Transcribes (+) strand ss mRNA.

Poxvirus, Phages N4, SPO2.

dsRNA viruses.

ssRNA (+) viruses.

Enzymes adding specific terminal groups to viral mRNA

Nucleotide Phosphohydrolase.
Guanylyl transferase. RNA methylases.

Poly (A) polymerase.

Converts 5'-ppp to 5'-PP. Adds guanylyl residue to 5'-pp in mRNA.

Methylates 5' end guanyl residues in mRNA.

Synthesizes 3' end poly (A) tail in mRNA.

Viruses synthesizing mRNA in virions

(e. g. poxviruses and reoviruses).

RNA- DNA transcription enzymes

Reverse transcriptase. RNase H (with above).

Polynucleotide ligase.

DNA-RNA hybrids; dsDNA.

 Degrades RNA in RNA-DNA hybrids.

Closes ss breaks in dsRNA.

Retroviruses.

-do­-

Nucleic acid replication or processing enzymes

DNA-dependent DNA polymerase.

DNases (exo- and endo-). Endoribonucleases.

Synthesizes dsDNA.

Break DNA strands and crosslinks.

mRNA processing.

Hepatitis B.

Pox-, retro- adenoviruses.

Ss mRNA viruses (e. g: poxviruses).

Other enzymes

Protein kinases

tRNA aminoaovlases.

Phosphorylate proteins.

Aminoacylate tDNA.

Retro-, orthomyxo- paramyxo,

herpes- and adenoviruses

Retroviruses