Unique structure of new serine tRNAs responsible for decoding leucine codon CUG in various Candida species and their putative ancestral tRNA genes

Structure Prediction of a Thermostable SR74 α-Amylase from Geobacillus stearothermophilus Expressed in CTG-Clade Yeast Meyerozyma guilliermondii Strain SO

“…A similar study also that showed C. albicans can tolerate up to 28.1% of leucine mis-incorporation contributed by the CUG ambiguity present [22]. Moreover, such phenomenon in C. albicans can be extended to C. guilliermondii (teleomorph M. guilliermondii) since their introns in the Ser-tRNA CGA are similar [23,24], further suggesting the very high occurrence rate of serine incorporation (95% to 97%) in a protein expressed in M. guilliermondii.…”

Structure Prediction of a Thermostable SR74 α-Amylase from Geobacillus stearothermophilus Expressed in CTG-Clade Yeast Meyerozyma guilliermondii Strain SO

“…A similar study also that showed C. albicans can tolerate up to 28.1% of leucine mis-incorporation contributed by the CUG ambiguity present [22]. Moreover, such phenomenon in C. albicans can be extended to C. guilliermondii (teleomorph M. guilliermondii) since their introns in the Ser-tRNA CGA are similar [23,24], further suggesting the very high occurrence rate of serine incorporation (95% to 97%) in a protein expressed in M. guilliermondii.…”

Endogenous Stochastic Decoding of the CUG Codon by Competing Ser- and Leu-tRNAs in Ascoidea asiatica

“…The AGA, CGA, and UGA isoacceptors (for UCU, UCG, and UCA codons, respectively) do not form monophyletic groups. Thus, the DM clade could have originated from any of these isoacceptors and not necessarily from a tRNA CGA ancestor, as suggested by the few tRNA sequences available 20 years ago [ 13 , 32 ].…”

The ‘polysemous’ codon—a codon with multiple amino acid assignment caused by dual specificity of tRNA identity

“…We believe that tRNA Ser CAG is the only molecule responsible for the leucine insertion corresponding to codon CUG in C.maltosa cells, based on the following obervations. We have purified and sequenced a number of leucine and serine tRNAs from Candida species, in which codon CUG is translated as serine, and failed in finding tRNA with the anticodon sequence potentially complementary to codon CUG other than tRNA Ser CAG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation). Futhermore, tRNA genes for serine and leucine from these Candida species were sequenced following the amplification by cloning and/or PCR methods, and we found that only tRNA Ser CAG is able to translate codon CUG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation).…”

“…A plausible evolutionary process is that group 1 would have arisen prior to group 2 after the genetic code change, which is speculated on the basis of the following observations. First, the homology between tRNA Ser CAGs in group 1 and its isoacceptor tRNAs for codon UCG is higher than that between the tRNA Ser CAG from C.cylindracea and its isoacceptor (Ueda et al ., 1994). Second, C.cylindracea (group 2) possesses high copy numbers of the tRNA Ser CAG genes (∼20 copies) on the diploid genome (Suzuki et al ., 1994), while low copy numbers (two or four copies) are observed for group 1 tRNA Ser CAG genes (Santos et al ., 1993; Sugiyama et al ., 1995; T.Suzuki, personal observations).…”

Structure Prediction of a Thermostable SR74 α-Amylase from Geobacillus stearothermophilus Expressed in CTG-Clade Yeast Meyerozyma guilliermondii Strain SO

“…A similar study also that showed C. albicans can tolerate up to 28.1% of leucine mis-incorporation contributed by the CUG ambiguity present [22]. Moreover, such phenomenon in C. albicans can be extended to C. guilliermondii (teleomorph M. guilliermondii) since their introns in the Ser-tRNA CGA are similar [23,24], further suggesting the very high occurrence rate of serine incorporation (95% to 97%) in a protein expressed in M. guilliermondii.…”

Endogenous Stochastic Decoding of the CUG Codon by Competing Ser- and Leu-tRNAs in Ascoidea asiatica

“…The AGA, CGA, and UGA isoacceptors (for UCU, UCG, and UCA codons, respectively) do not form monophyletic groups. Thus, the DM clade could have originated from any of these isoacceptors and not necessarily from a tRNA CGA ancestor, as suggested by the few tRNA sequences available 20 years ago [ 13 , 32 ].…”

The ‘polysemous’ codon—a codon with multiple amino acid assignment caused by dual specificity of tRNA identity

“…We believe that tRNA Ser CAG is the only molecule responsible for the leucine insertion corresponding to codon CUG in C.maltosa cells, based on the following obervations. We have purified and sequenced a number of leucine and serine tRNAs from Candida species, in which codon CUG is translated as serine, and failed in finding tRNA with the anticodon sequence potentially complementary to codon CUG other than tRNA Ser CAG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation). Futhermore, tRNA genes for serine and leucine from these Candida species were sequenced following the amplification by cloning and/or PCR methods, and we found that only tRNA Ser CAG is able to translate codon CUG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation).…”

“…A plausible evolutionary process is that group 1 would have arisen prior to group 2 after the genetic code change, which is speculated on the basis of the following observations. First, the homology between tRNA Ser CAGs in group 1 and its isoacceptor tRNAs for codon UCG is higher than that between the tRNA Ser CAG from C.cylindracea and its isoacceptor (Ueda et al ., 1994). Second, C.cylindracea (group 2) possesses high copy numbers of the tRNA Ser CAG genes (∼20 copies) on the diploid genome (Suzuki et al ., 1994), while low copy numbers (two or four copies) are observed for group 1 tRNA Ser CAG genes (Santos et al ., 1993; Sugiyama et al ., 1995; T.Suzuki, personal observations).…”

Structure Prediction of a Thermostable SR74 α-Amylase from Geobacillus stearothermophilus Expressed in CTG-Clade Yeast Meyerozyma guilliermondii Strain SO

“…A similar study also that showed C. albicans can tolerate up to 28.1% of leucine mis-incorporation contributed by the CUG ambiguity present [22]. Moreover, such phenomenon in C. albicans can be extended to C. guilliermondii (teleomorph M. guilliermondii) since their introns in the Ser-tRNA CGA are similar [23,24], further suggesting the very high occurrence rate of serine incorporation (95% to 97%) in a protein expressed in M. guilliermondii.…”

Endogenous Stochastic Decoding of the CUG Codon by Competing Ser- and Leu-tRNAs in Ascoidea asiatica

“…The AGA, CGA, and UGA isoacceptors (for UCU, UCG, and UCA codons, respectively) do not form monophyletic groups. Thus, the DM clade could have originated from any of these isoacceptors and not necessarily from a tRNA CGA ancestor, as suggested by the few tRNA sequences available 20 years ago [ 13 , 32 ].…”

The ‘polysemous’ codon—a codon with multiple amino acid assignment caused by dual specificity of tRNA identity

“…We believe that tRNA Ser CAG is the only molecule responsible for the leucine insertion corresponding to codon CUG in C.maltosa cells, based on the following obervations. We have purified and sequenced a number of leucine and serine tRNAs from Candida species, in which codon CUG is translated as serine, and failed in finding tRNA with the anticodon sequence potentially complementary to codon CUG other than tRNA Ser CAG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation). Futhermore, tRNA genes for serine and leucine from these Candida species were sequenced following the amplification by cloning and/or PCR methods, and we found that only tRNA Ser CAG is able to translate codon CUG (Yokogawa et al ., 1992; Ohama et al ., 1993; Suzuki et al ., 1994; Ueda et al ., 1994; our unpublished observation).…”

“…A plausible evolutionary process is that group 1 would have arisen prior to group 2 after the genetic code change, which is speculated on the basis of the following observations. First, the homology between tRNA Ser CAGs in group 1 and its isoacceptor tRNAs for codon UCG is higher than that between the tRNA Ser CAG from C.cylindracea and its isoacceptor (Ueda et al ., 1994). Second, C.cylindracea (group 2) possesses high copy numbers of the tRNA Ser CAG genes (∼20 copies) on the diploid genome (Suzuki et al ., 1994), while low copy numbers (two or four copies) are observed for group 1 tRNA Ser CAG genes (Santos et al ., 1993; Sugiyama et al ., 1995; T.Suzuki, personal observations).…”