Mammalian reovirus core protein micro 2 initiates at the first start codon and is acetylated

Mammalian reovirus is an enteric virus that contains a double-stranded RNA genome. The genome consists of ten RNA segments that encode eight structural and three non-structural proteins. The structural proteins form a double-layered structure. The innermost layer, called the core, consists of five p...

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Bibliographic Details
Published in:Rapid communications in mass spectrometry 2002, Vol.16 (24), p.2317-2324
Main Authors: Swanson, Magdalena I, She, Yi-Min, Ens, Werner, Brown, Earl G, Coombs, Kevin M
Format: Article
Language:English
Subjects:
Acetylation
Amino Acid Sequence
Base Sequence
Cells, Cultured
Codon, Initiator - genetics
Molecular Sequence Data
Molecular Weight
Protein Biosynthesis
Protein Processing, Post-Translational
Reoviridae - chemistry
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Viral Core Proteins - chemistry
Viral Core Proteins - genetics
Viral Proteins - chemistry
Viral Proteins - genetics
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Summary:Mammalian reovirus is an enteric virus that contains a double-stranded RNA genome. The genome consists of ten RNA segments that encode eight structural and three non-structural proteins. The structural proteins form a double-layered structure. The innermost layer, called the core, consists of five proteins (lambda1, lambda2, lambda3, micro 2, and sigma2). Protein lambda3 is the RNA-dependent RNA polymerase (RdRp) and micro 2 is thought to be an RdRp cofactor. Translation of most reovirus proteins is known to commence at the first start codon. However, the translation initiation site of the viral core protein micro 2, encoded by the M1 RNA segment, has been in dispute. Although the theoretical molecular weight of micro 2 is 83 267 Da the actual molecular weight is unknown because micro 2 runs aberrantly in SDS-PAGE and has resisted characterization by Edman degradation, indicating that the amino terminus is post-translationally modified. In this study, we used proteolysis coupled with MALDI-Qq-TOFMS to determine that translation of micro 2 initiates at the first AUG codon, that its actual molecular weight approximates the theoretical value of 83 kDa, that the amino terminal methionine residue is removed, and that the next amino acid (alanine) is post-translationally acetylated.
ISSN:0951-4198