The cDNA and protein structures of Xenopus metaxin 3, along with those of Xenopus metaxins 1 and 2, have been characterized. A protein of 309 amino acid residues is encoded by X. laevis metaxin 3 (XMTX3) cDNA. In comparison, the cDNA of X. laevis metaxin 1 (XMTX1) specifies a protein of 320 residues, while the metaxin 2 cDNAs of X. laevis (XMTX2) and X. tropicalis (SMTX2) both specify proteins of 274 amino acids. Aligning the amino acid sequences of XMTX3 and XMTX1 showed 39% identities; 22% identities were found for XMTX3 and XMTX2. However, 55% amino acid identities were revealed in aligning the XMTX3 and zebrafish metaxin 3 sequences. The construction of a phylogenetic tree gave further evidence for the existence of three distinct groups of metaxin genes and their common ancestry. Two conserved protein domains are present in each of the Xenopus metaxins: a glutathione S-transferase (GST) domain and a thioredoxin-like domain. The protein secondary structure predicted for the Xenopus metaxins is dominated by regions of alpha helix which alternate with regions that are neither alpha helix nor beta strand.
|Original language||English (US)|
|Number of pages||8|
|Journal||DNA Sequence - Journal of DNA Sequencing and Mapping|
|State||Published - Aug 2005|
Bibliographical noteFunding Information:
This research was carried out with the financial support of a grant from the Minnesota Medical Foundation.
- Amino acid sequence
- Protein domains
- Protein secondary structure
- Xenopus laevis
- cDNA sequence