YtfB, an OapA Domain-Containing Protein, Is a New Cell Division Protein in Escherichia coli

Bacterial cell-wall quantification by a modified low volume Nelson-Somogyi method and its use with different sugars

The study of peptidoglycan binding proteins frequently requires in vitro binding assays in which the isolated peptidoglycan used as substrate has to be carefully quantified. Here we describe an easy and sensitive assay for the quantification of peptidoglycan based on a modified Nelson-Somogyi reducing sugar assay. We report the response of this assay to different common sugars and adapt its use to peptidoglycan samples that have been subjected to acid hydrolysis. This method showed a better sensitivity than the peptidoglycan quantification method based on the acid detection of diaminopimelic acid. The method described in this work besides being valuable in the characterization of peptidoglycan binding proteins, is also useful for quantification of reducing monosaccharides or of polysaccharides after acid or hydrolysis.

TAGOPSIN: collating taxa-specific gene and protein functional and structural information

Background

The wealth of biological information available nowadays in public databases has triggered an unprecedented rise in multi-database search and data retrieval for obtaining detailed information about key functional and structural entities. This concerns investigations ranging from gene or genome analysis to protein structural analysis. However, the retrieval of interconnected data from a number of different databases is very often done repeatedly in an unsystematic way.

Results

Here, we present TAxonomy, Gene, Ontology, Protein, Structure INtegrated (TAGOPSIN), a command line program written in Java for rapid and systematic retrieval of select data from seven of the most popular public biological databases relevant to comparative genomics and protein structure studies. The program allows a user to retrieve organism-centred data and assemble them in a single data warehouse which constitutes a useful resource for several biological applications. TAGOPSIN was tested with a number of organisms encompassing eukaryotes, prokaryotes and viruses. For example, it successfully integrated data for about 17,000 UniProt entries of Homo sapiens and 21 UniProt entries of human coronavirus.

Conclusion

TAGOPSIN demonstrates efficient data integration whereby manipulation of interconnected data is more convenient than doing multi-database queries. The program facilitates for instance interspecific comparative analyses of protein-coding genes in a molecular evolutionary study, or identification of taxa-specific protein domains and three-dimensional structures. TAGOPSIN is available as a JAR file at https://github.com/ebundhoo/TAGOPSIN and is released under the GNU General Public License.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-021-04429-5.

DrpB (YedR) Is a Nonessential Cell Division Protein in Escherichia coli

A thorough understanding of bacterial cell division requires identifying and characterizing all of the proteins that participate in this process. Our discovery of DrpB brings us one step closer to this goal in E. coli.

We report that the small Escherichia coli membrane protein DrpB (formerly YedR) is involved in cell division. We discovered DrpB in a screen for multicopy suppressors of a ΔftsEX mutation that prevents divisome assembly when cells are plated on low ionic strength medium, such as lysogeny broth without NaCl. Characterization of DrpB revealed that (i) translation initiates at an ATG annotated as codon 22 rather than the GTG annotated as codon 1, (ii) DrpB localizes to the septal ring when cells are grown in medium of low ionic strength but localization is greatly reduced in medium of high ionic strength, (iii) overproduction of DrpB in a ΔftsEX mutant background improves recruitment of the septal peptidoglycan synthase FtsI, implying multicopy suppression works by rescuing septal ring assembly, (iv) a ΔdrpB mutant divides quite normally, but a ΔdrpB ΔdedD double mutant has a strong division and viability defect, albeit only in medium of high ionic strength, and (v) DrpB homologs are found in E. coli and a few closely related enteric bacteria, but not outside this group. In sum, DrpB is a poorly conserved nonessential division protein that improves the efficiency of cytokinesis under suboptimal conditions. Proteins like DrpB are likely to be a widespread feature of the bacterial cell division apparatus, but they are easily overlooked because mutants lack obvious shape defects.

IMPORTANCE A thorough understanding of bacterial cell division requires identifying and characterizing all of the proteins that participate in this process. Our discovery of DrpB brings us one step closer to this goal in E. coli.

The novel E. coli cell division protein, YtfB, plays a role in eukaryotic cell adhesion

Characterisation of protein function based solely on homology searches may overlook functions under specific environmental conditions, or the possibility of a protein having multiple roles. In this study we investigated the role of YtfB, a protein originally identified in a genome-wide screen to cause inhibition of cell division, and has demonstrated to localise to the Escherichia coli division site with some degree of glycan specificity. Interestingly, YtfB also shows homology to the virulence factor OapA from Haemophilus influenzae, which is important for adherence to epithelial cells, indicating the potential of additional function(s) for YtfB. Here we show that E. coli YtfB binds to N’acetylglucosamine and mannobiose glycans with high affinity. The loss of ytfB results in a reduction in the ability of the uropathogenic E. coli strain UTI89 to adhere to human kidney cells, but not to bladder cells, suggesting a specific role in the initial adherence stage of ascending urinary tract infections. Taken together, our results suggest a role for YtfB in adhesion to specific eukaryotic cells, which may be additional, or complementary, to its role in cell division. This study highlights the importance of understanding the possible multiple functions of proteins based on homology, which may be specific to different environmental conditions.