Biomedical subjects

C Hotzy

Publications and source records attributed to C Hotzy.

5 recordsLinked to original sources

PubMed2006

Idiopathic generalized epilepsy phenotypes associated with different EFHC1 mutations.

We sequenced 61 patients with various idiopathic generalized epilepsy (IGE) syndromes for mutations in the EFHC1 gene. We detected three novel heterozygous missense mutations (I174V, C259Y, A394S) and one possibly pathogenic variant in the 3' UTR (2014t>c). The mutation I174V was also detected in 1 of 372 screened patients with temporal lobe epilepsy. We conclude that mutations in the EFHC1 gene may underlie different types of epilepsy syndromes.

3' Untranslated Regions↗

PubMed2006

Mutations in the CLCN2 gene are a rare cause of idiopathic generalized epilepsy syndromes.

Mutations in the chloride channel gene CLCN2 have been reported in families with generalized and focal epilepsy syndromes. To evaluate the contribution of mutations in the CLCN2 gene to the etiology of epilepsies in our population, we screened 96 patients with different epilepsy syndromes and a putative genetic background. No definite mutations were found in our study population. We conclude that mutations in the CLCN2 gene are only a rare cause of idiopathic generalized epilepsy.

CLC-2 Chloride Channels↗

PubMed2001

Characterization of an S-layer glycoprotein produced in the course of S-layer variation of Bacillus stearothermophilus ATCC 12980 and sequencing and cloning of the sbsD gene encoding the protein moiety.

The cell surface of Bacillus stearothermophilus ATCC 12980 is completely covered by an oblique lattice which consists of the S-layer protein SbsC. On SDS-polyacrylamide gels, the mature S-layer protein migrates as a single band with an apparent molecular mass of 122 kDa. During cultivation of B. stearothermophilus ATCC 12980 at 67 degrees C instead of 55 degrees C, a variant developed that had a secondary cell wall polymer identical to that of the wild-type strain, but it carried an S-layer glycoprotein that could be separated on SDS-polyacrylamide gels into four bands with apparent molecular masses of 92, 118, 150 and 175 kDa. After deglycosylation, only a single protein band with a molecular mass of 92 kDa remained. The complete nucleotide sequence encoding the protein moiety of this S-layer glycoprotein, termed SbsD, was established by PCR and inverse PCR. The sbsD gene of 2,709 bp is predicted to encode a protein of 96.2 kDa with a 30-amino-acid signal peptide. Within the 807 bp encoding the signal peptide and the N-terminal sequence (amino acids 31-269), different nucleotides for sbsD and sbsC were observed in 46 positions, but 70% of these mutations were silent, thus leading to a level of identity of 95% for the N-terminal parts. The level of identity of the remaining parts of SbsD and SbsC was below 10%, indicating that the lysine-, tyrosine- and arginine-rich N-terminal region in combination with a distinct type of secondary cell wall polymer remained conserved upon S-layer variation. The sbsD sequence encoding the mature S-layer protein cloned into the pET28a vector led to stable expression in Escherichia coli HMS174(DE3). This is the first example demonstrating that S-layer variation leads to the synthesis of an S-layer glycoprotein.

Amino Acid Sequence↗

PubMed1998

The S-layer proteins of two Bacillus stearothermophilus wild-type strains are bound via their N-terminal region to a secondary cell wall polymer of identical chemical composition.

Two Bacillus stearothermophilus wild-type strains were investigated regarding a common recognition and binding mechanism between the S-layer protein and the underlying cell envelope layer. The S-layer protein from B. stearothermophilus PV72/p6 has a molecular weight of 130,000 and assembles into a hexagonally ordered lattice. The S-layer from B. stearothermophilus ATCC 12980 shows oblique lattice symmetry and is composed of subunits with a molecular weight of 122,000. Immunoblotting, peptide mapping, N-terminal sequencing of the whole S-layer protein from B. stearothermophilus ATCC 12980 and of proteolytic cleavage fragments, and comparison with the S-layer protein from B. stearothermophilus PV72/p6 revealed that the two S-layer proteins have identical N-terminal regions but no other extended structurally homologous domains. In contrast to the heterogeneity observed for the S-layer proteins, the secondary cell wall polymer isolated from peptidoglycan-containing sacculi of the different strains showed identical chemical compositions and comparable molecular weights. The S-layer proteins could bind and recrystallize into the appropriate lattice type on native peptidoglycan-containing sacculi from both organisms but not on those extracted with hydrofluoric acid, leading to peptidoglycan of the A1gamma chemotype. Affinity studies showed that only proteolytic cleavage fragments possessing the complete N terminus of the mature S-layer proteins recognized native peptidoglycan-containing sacculi as binding sites or could associate with the isolated secondary cell wall polymer, while proteolytic cleavage fragments missing the N-terminal region remained unbound. From the results obtained in this study, it can be concluded that S-layer proteins from B. stearothermophilus wild-type strains possess an identical N-terminal region which is responsible for anchoring the S-layer subunits to a secondary cell wall polymer of identical chemical composition.

Amino Acid Sequence↗

PubMed1997

Evidence that the N-terminal part of the S-layer protein from Bacillus stearothermophilus PV72/p2 recognizes a secondary cell wall polymer.

The S-layer of Bacillus stearothermophilus PV72/p2 shows oblique lattice symmetry and is composed of identical protein subunits with a molecular weight of 97,000. The isolated S-layer subunits could bind and recrystallize into the oblique lattice on native peptidoglycan-containing sacculi which consist of peptidoglycan of the A1gamma chemotype and a secondary cell wall polymer with an estimated molecular weight of 24,000. The secondary cell wall polymer could be completely extracted from peptidoglycan-containing sacculi with 48% HF, indicating the presence of phosphodiester linkages between the polymer chains and the peptidoglycan backbone. The cell wall polymer was composed mainly of GlcNAc and ManNAc in a molar ratio of 4:1, constituted about 20% of the peptidoglycan-containing sacculus dry weight, and was also detected in the fraction of the S-layer self-assembly products. Extraction experiments and recrystallization of the whole S-layer protein and proteolytic cleavage fragments confirmed that the secondary cell wall polymer is responsible for anchoring the S-layer subunits by the N-terminal part to the peptidoglycan-containing sacculi. In addition to this binding function, the cell wall polymer was found to influence the in vitro self-assembly of the guanidinium hydrochloride-extracted S-layer protein. Chemical modification studies further showed that the secondary cell wall polymer does not contribute significant free amino or carboxylate groups to the peptidoglycan-containing sacculi.

ATP-Binding Cassette Transporters↗