PROSITE documentation PDOC51743
Alphavirus-like methyltransferase (MT) domain profile


The αvirus-like methyltransferase (MT) domain is found in a superfamily of positive-strand RNA viruses that includes αviruses, hepatis E virus, and rubella virus, that are animal viruses, as well as a large number of plant viruses: tobra-, tobamo-, bromo-, tymo-, potex-, and carlaviruses and other groups. The αvirus-like MT domain is involved in methylation of the cap during viral RNA maturation: S-adenosylmethionine (AdoMet) reacts with GTP to yield 7-methyl-GTP (m(7)GTP) and S-adenosylhomocysteine (AdoHcy). In the presence of AdoMet, GTP also reacts with the αvirus-like MT domain to form a unique covalent complex, 7-methyl-GMP-αvirus-like MT domain [1,2,3].

The αvirus-like MT domain encompasses four distinct conserved motifs, with motif I, II and IV containing an invariant His residue, the AspXXArg signature and an invariant Tyr residue, respectively. It is predicted to belong to the α/β class of domain structure [1,2,3].

Some proteins known to contain a αvirus-like MT domain are listed below:

  • Hepatitis E virus (HEV) non-structural polyprotein pORF1.
  • Sindbis virus (SINV) non-structural polyprotein.
  • Semliki forest virus (SFV) non-structural polyprotein.
  • Ross river virus (RRV) non-structural polyprotein.
  • O'nyong-nyong virus (ONNV) non-structural polyprotein.
  • Venezuelan equine encephalitis virus (VEEV) non-structural polyprotein.
  • Tobacco rattle virus (TRV) replicase large subunit.
  • Alfalfa mosaic virus (AMV) replication protein 1a.
  • Brome mosaic virus (BMV) replication protein 1a.
  • Cucumber mosaic virus (CMV) replication protein 1a.
  • Beet necrotic yellow vein virus (BNYVV) replicase.
  • Rubella virus (RUBV) non-structural polyprotein p200.
  • Ononis yellow mosaic virus RNA replicase polyprotein.
  • Eggplant mosaic virus RNA replicase polyprotein.
  • Kennedya yellow mosaic virus (KYMV) RNA replicase polyprotein.
  • Turnip yellow mosaic virus RNA replicase polyprotein.
  • White clover mosaic virus (WCMV) RNA replication protein.
  • Narcissus mosaic virus (NMV) RNA replication protein.
  • Potato virus X (PVX) RNA replication protein.
  • Papaya mosaic potexvirus (PMV) RNA replication protein.
  • Foxtail mosaic virus RNA replication protein.
  • Potato virus M (PVM) RNA replication protein.
  • Apple chlorotic leaf spot virus (ACLSV) RNA-directed RNA polymerase.

The profile we developed covers the entire αvirus-like MT domain.

Last update:

January 2015 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

ALPHAVIRUS_MT, PS51743; Alphavirus-like methyltransferase (MT) domain profile  (MATRIX)


1AuthorsRozanov M.N. Koonin E.V. Gorbalenya A.E.
TitleConservation of the putative methyltransferase domain: a hallmark of the 'Sindbis-like' supergroup of positive-strand RNA viruses.
SourceJ. Gen. Virol. 73:2129-2134(1992).
PubMed ID1645151

2AuthorsAhola T. Laakkonen P. Vihinen H. Kaeaeriaeinen L.
TitleCritical residues of Semliki Forest virus RNA capping enzyme involved in methyltransferase and guanylyltransferase-like activities.
SourceJ. Virol. 71:392-397(1997).
PubMed ID8985362

3AuthorsVlot A.C. Menard A. Bol J.F.
TitleRole of the alfalfa mosaic virus methyltransferase-like domain in negative-strand RNA synthesis.
SourceJ. Virol. 76:11321-11328(2002).
PubMed ID12388692

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