Biomedical subjects

G Mannhaupt

Publications and source records attributed to G Mannhaupt.

21 records · Page 2Linked to original sources

PubMed1985

Cytochrome b, the var 1 protein, and subunits I and III of cytochrome c oxidase are synthesized without transient presequences in Saccharomyces cerevisiae.

The N-termini of four mitochondrial translation products, the var 1 protein, cytochrome b, and subunits I and III of cytochrome c oxidase have been characterized in Saccharomyces cerevisiae and compared with the known DNA sequences of the respective structural genes. The four mature proteins correspond to the predicted primary translation products and retain the formylated methionine residue. Thus, subunit II of cytochrome c oxidase studied previously [Pratje et al. (1983) EMBO J.2, 1049-1054] is so far the only mitochondrial translation product carrying a N-terminal-extended transient presequence in S. cerevisiae.

Amino Acid Sequence↗

PubMed1983

A nuclear mutation prevents processing of a mitochondrially encoded membrane protein in Saccharomyces cerevisiae.

Subunit II of cytochrome oxidase is encoded by the mitochondrial OXI1 gene in Saccharomyces cerevisiae. The temperature-sensitive nuclear pet mutant ts2858 has an apparent higher mol. wt. subunit II when analyzed on lithium dodecylsulfate (LiDS) polyacrylamide gels. However, on LiDS-6M urea gels the apparent mol. wt. of the wild-type protein exceeds that of the mutant. Partial revertants of mutant ts2858 that produce both the wild-type and mutant form of subunit II were isolated. The two forms of subunit II differ at the N-terminal part of the molecule as shown by constructing and analyzing nuclear ts2858 and mitochondrial chain termination double mutants. The presence of the primary translation product in the mutant and of the processed form in the wild-type lacking 15 amino-terminal residues was demonstrated by radiolabel protein sequencing. Comparison of the known DNA sequence with the partial protein sequence obtained reveals that six of the 15 residues are hydrophilic and, unlike most signal sequences, this transient sequence does not contain extended hydrophobic parts. The nuclear mutation ts2858 preventing post-translational processing of cytochrome oxidase subunit II lies either in the gene for a protease or an enzyme regulating a protease.

Cell Nucleus↗

PubMedDate not supplied

Analysis of the THR4 region on chromosome III of the yeast Saccharomyces cerevisiae.

The gene encoding threonine synthase (THR4) from the yeast Saccharomyces cerevisiae was cloned by complementation of a thr4 mutant. This gene was also found on a lambda clone (5239) consisting of a fragment of chromosome III inserted in the vector lambdaMG3. The THR4 gene encodes a protein of 514 amino acids (M.W. 58 kDa), which has extensive homologies with E. coli threonine synthase (thrC) and B subtilis threonine synthase. The 5' flanking region of the gene contains three regulatory sequences [TGACT(C)] for the general amino acid control (GCN). About 130 bp downstream of the THR4 gene another large open reading frame (563 amino acids) is found in the opposite orientation. This may imply that this open reading frame, called CTR86, shares a terminator region with THR4. The function of the protein encoded by CTR86 is not yet clear, but the fact that the upstream region contains a GCN4 responsive site suggests that the gene product may also be involved in amino acid biosynthesis.

Amino Acid Sequence↗