scholarly journals Identification and Characterization of Protease-Resistant SecA Fragments: SecA Has Two Membrane-Integral Forms

1998 ◽  
Vol 180 (3) ◽  
pp. 527-537 ◽  
Author(s):  
Xianchuan Chen ◽  
Timothy Brown ◽  
Phang C. Tai
Keyword(s):  
Atp Hydrolysis ◽  
Protein Translocation ◽  
Chemical Extraction ◽  
Sequencing Analysis ◽  
High Concentration ◽  
Conducting Channel ◽  
Specific Antibodies ◽  
Integral Forms ◽  
Identification And Characterization

ABSTRACT We have identified and characterized the protease-resistant SecA fragments (X. Chen, H. Xu, and P. C. Tai, J. Biol. Chem. 271:29698–29706, 1996) through immunodetection with region-specific antibodies, chemical extraction, and sequencing analysis. The 66-, 36-, and 27-kDa proteolytic fragments in the membranes all start at Met1, whereas the 48-kDa fragment starts at Glu361. The overlapping of the sequences of the 66- and 48-kDa fragments indicates that they are derived from different SecA molecules. These two fragments were generated differently in response to ATP hydrolysis and protein translocation. Furthermore, the presence of membrane is required for the generation of the 48-kDa fragment but not for that of the 66-kDa fragment. These data suggest that there are two different integral forms of SecA in the membrane: SecASand SecAM. The combination of these two forms of SecA has several membrane-interacting domains. Both forms of SecA are integrated in the membrane, since both the 48- and 66-kDa fragments could be derived from urea- or Na2CO3-washed membranes. Moreover, all fragments are resistant to extraction with a high concentration of salt or with heparin, but the membrane-specific 48-kDa SecA domain is more sensitive to Na2CO3 or urea extraction. This suggests that this domain may interact with other membrane proteins in an aqueous microenvironment and therefore may form a part of the protein-conducting channel.

scholarly journals Channel crossing: how are proteins shipped across the bacterial plasma membrane?

2015 ◽  
Vol 370 (1679) ◽  
pp. 20150025 ◽  
Author(s):  
Ian Collinson ◽  
Robin A. Corey ◽  
William J. Allen
Keyword(s):  
Free Energy ◽  
Plasma Membrane ◽  
Atp Hydrolysis ◽  
Protein Translocation ◽  
Transmembrane Protein ◽  
Conducting Channel ◽  
Outstanding Problem ◽  
Unfolded State ◽  
Tat System ◽  
Folded Proteins

The structure of the first protein-conducting channel was determined more than a decade ago. Today, we are still puzzled by the outstanding problem of protein translocation—the dynamic mechanism underlying the consignment of proteins across and into membranes. This review is an attempt to summarize and understand the energy transducing capabilities of protein-translocating machines, with emphasis on bacterial systems: how polypeptides make headway against the lipid bilayer and how the process is coupled to the free energy associated with ATP hydrolysis and the transmembrane protein motive force. In order to explore how cargo is driven across the membrane, the known structures of the protein-translocation machines are set out against the background of the historic literature, and in the light of experiments conducted in their wake. The paper will focus on the bacterial general secretory (Sec) pathway (SecY-complex), and its eukaryotic counterpart (Sec61-complex), which ferry proteins across the membrane in an unfolded state, as well as the unrelated Tat system that assembles bespoke channels for the export of folded proteins.

Review on Extraction and Characterization of Castor Seed Oil

2014 ◽  
Vol 625 ◽  
pp. 916-919
Author(s):  
Muhammad Fitri Jamil ◽  
Yoshimitsu Uemura ◽  
Norridah Osman ◽  
Katsuki Kusakabe ◽  
Suzana Yusup
Keyword(s):  
Ricinoleic Acid ◽  
Vegetable Oil ◽  
Castor Oil ◽  
Seed Oil ◽  
Chemical Extraction ◽  
High Concentration ◽  
Mechanical Extraction

Extraction of castor oil is important in determination of the quality of castor oil extracted. The quality of castor oil being extracted has to meet the ASTM standard that has been produced. The way of extraction can be either mechanical extraction or chemical extraction that is practically used in the industry which give the highest yield of oil extracted. Castor oil is mainly composed of ricinoleic acid in high concentration. It is a unique vegetable oil that contains high content of fatty hydroxyacid.

scholarly journals Identification and Characterization of a New Staphylococcal Enterotoxin-Related Putative Toxin Encoded by Two Kinds of Plasmids

2003 ◽  
Vol 71 (10) ◽  
pp. 6088-6094 ◽  
Author(s):  
Katsuhiko Omoe ◽  
Dong-Liang Hu ◽  
Hiromi Takahashi-Omoe ◽  
Akio Nakane ◽  
Kunihiro Shinagawa
Keyword(s):  
Escherichia Coli ◽  
Expression System ◽  
Staphylococcal Enterotoxin ◽  
Nucleotide Sequencing ◽  
Sequencing Analysis ◽  
T Cell Stimulation ◽  
Putative Toxin ◽  
Identification And Characterization ◽  
Related Plasmid

ABSTRACT We identified and characterized a novel staphylococcal enterotoxin-like putative toxin, which is named SER. Nucleotide sequencing analysis of the ser gene revealed that ser was most closely related to the seg gene. The ser gene product, SER, was successfully expressed as a recombinant protein in an Escherichia coli expression system, and recombinant SER (rSER) showed significant T-cell stimulation activity. The SER production in ser-harboring Staphylococcus aureus strains was confirmed by Western blot analysis using anti-rSER antibody. Moreover, ser was seen to be encoded by at least two types of plasmids. In particular, one kind of plasmid encoding the ser gene has been known as a sed- and sej-carrying pIB485-related plasmid.

scholarly journals Identification and Characterization of a Novel Aminoglycoside 3''-Nucleotidyltransferase, ANT(3'')-IId, From Acinetobacter lwoffii

2021 ◽  
Vol 12 ◽  
Author(s):  
Jialei Liang ◽  
Kexin Zhou ◽  
Qiaoling Li ◽  
Xu Dong ◽  
Peiyao Zhang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Amino Acid Identity ◽  
Parameter Analysis ◽  
Sequencing Analysis ◽  
The Novel ◽  
Enzyme Kinetic Parameter ◽  
Animal Farm ◽  
Sequence Characteristics ◽  
Identification And Characterization

A novel plasmid-encoded aminoglycoside 3''-nucleotidyltransferase ANT(3")-IId, was discovered in Acinetobacter lwoffi strain H7 isolated from a chick on an animal farm in Wenzhou, China. The whole-genome of A. lwoffii H7 consisted of one chromosome and five plasmids (pH7-250, pH7-108, pH7-68, pH7-48, and pH7-11). ant(3")-IId was identified as being encoded on pH7-250, sharing the highest amino acid identity of 50.64% with a function-known resistance gene, ant(3")-IIb (KB849358.1). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 3"-nucleotidyltransferase. The ant(3")-IId gene conferred resistance to spectinomycin and streptomycin [the minimum inhibitory concentration (MIC) levels of both increased 16-fold compared with the control strain]. Consistent with the MIC data, kinetic analysis revealed a narrow substrate profile including spectinomycin and streptomycin, with Kcat/Km ratios of 4.99 and 4.45×103M−1 S−1, respectively. Sequencing analysis revealed that the ant(3")-IId gene was associated with insertion sequences (IS) element [ΔISAba14-ΔISAba14-hp-orf-orf-orf1-ant(3")-IId], and ant(3")-IId were identified in plasmids from various Acinetobacter species. This study of the novel aminoglycoside 3"-nucleotidyltranferase ANT(3")-IId helps us further understand the functional and sequence characteristics of aminoglycoside 3"-nucleotidyltranferases, highlights the risk of resistance gene transfer among Acinetobacter species and suggests that attention should be given to the emergence of new aminoglycoside 3"-nucleotidyltranferase genes.

Sign in / Sign up

Export Citation Format

Share Document