Sialic acid (N-acetyl neuraminic acid) utilization by Bacteroides fragilis requires a novel N-acetyl mannosamine epimerase.

J Bacteriol 2009 Jun 20;191(11):3629-38. Epub 2009 Mar 20.

Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA.

We characterized the nanLET operon in Bacteroides fragilis, whose products are required for the utilization of the sialic acid N-acetyl neuraminic acid (NANA) as a carbon and energy source. The first gene of the operon is nanL, which codes for an aldolase that cleaves NANA into N-acetyl mannosamine (manNAc) and pyruvate. The next gene, nanE, codes for a manNAc/N-acetylglucosamine (NAG) epimerase, which, intriguingly, possesses more similarity to eukaryotic renin binding proteins than to other bacterial NanE epimerase proteins. Unphosphorylated manNAc is the substrate of NanE, while ATP is a cofactor in the epimerase reaction. The third gene of the operon is nanT, which shows similarity to the major transporter facilitator superfamily and is most likely to be a NANA transporter. Deletion of any of these genes eliminates the ability of B. fragilis to grow on NANA. Although B. fragilis does not normally grow with manNAc as the sole carbon source, we isolated a B. fragilis mutant strain that can grow on this substrate, likely due to a mutation in a NAG transporter; both manNAc transport and NAG transport are affected in this strain. Deletion of the nanE epimerase gene or the rokA hexokinase gene, whose product phosphorylates NAG, in the manNAc-enabled strain abolishes growth on manNAc. Thus, B. fragilis possesses a new pathway of NANA utilization, which we show is also found in other Bacteroides species.

Download full-text PDF

Source
http://dx.doi.org/10.1128/JB.00811-08DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2681899PMC
June 2009
2 Reads

Publication Analysis

Top Keywords

utilization bacteroides
8
neuraminic acid
8
fragilis grow
8
n-acetyl mannosamine
8
gene operon
8
nane epimerase
8
bacteroides fragilis
8
sialic acid
8
acid n-acetyl
8
n-acetyl neuraminic
8
fragilis
6
nana
5
epimerase
5
mannac
5
gene
5
nana transporter
4
transporter deletion
4
deletion genes
4
genes eliminates
4
carbon source
4

Altmetric Statistics

References

(Supplied by CrossRef)

Similar Publications