31138628, J Bacteriol. 2019 Jul 10;201(15):e00109-19. doi: 10.1128/JB.00109-19. Print 2019 Aug 1.

Characterization method

electrophoretic mobility shift assay,enzyme activity assay

Genomic accession number


Nucelotide position range







Bacillus subtilis/1423

Degradation or Biosynthesis


Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

ytaP 1 - 900 (-) CDS No
msmR 1118 - 2152 (+) TF: DBD-Pfam|LacI,DBD-SUPERFAMILY|0044558 No
msmE 2186 - 3466 (+) STP: STP|SBP_bac_1 No
amyD 3459 - 4370 (+) TC: gnl|TC-DB|O51924|3.A.1.1.7 Yes
amyC 4367 - 5197 (+) TC: gnl|TC-DB|Q8RJU8|3.A.1.1.18 Yes
melA 5217 - 6515 (+) CAZyme: GH4 Yes




31138628, J Bacteriol. 2019 Jul 10;201(15):e00109-19. doi: 10.1128/JB.00109-19. Print 2019 Aug 1.


The melREDCA Operon Encodes a Utilization System for the Raffinose Family of Oligosaccharides in Bacillus subtilis.


Morabbi Heravi K, Watzlawick H, Altenbuchner J


Bacillus subtilis is a heterotrophic soil bacterium that hydrolyzes different polysaccharides mainly found in the decomposed plants. These carbohydrates are mainly cellulose, hemicellulose, and the raffinose family of oligosaccharides (RFOs). RFOs are soluble alpha-galactosides, such as raffinose, stachyose, and verbascose, that rank second only after sucrose in abundance. Genome sequencing and transcriptome analysis of B. subtilis indicated the presence of a putative alpha-galactosidase-encoding gene (melA) located in the msmRE-amyDC-melA operon. Characterization of the MelA protein showed that it is a strictly Mn(2+)- and NAD(+)-dependent alpha-galactosidase able to hydrolyze melibiose, raffinose, and stachyose. Transcription of the msmER-amyDC-melA operon is under control of a sigma(A)-type promoter located upstream of msmR (P (msmR) ), which is negatively regulated by MsmR. The activity of P (msmR) was induced in the presence of melibiose and raffinose. MsmR is a transcriptional repressor that binds to two binding sites at P (msmR) located upstream of the -35 box and downstream of the transcriptional start site. MsmEX-AmyCD forms an ATP-binding cassette (ABC) transporter that probably transports melibiose into the cell. Since msmRE-amyDC-melA is a melibiose utilization system, we renamed the operon melREDCAIMPORTANCEBacillus subtilis utilizes different polysaccharides produced by plants. These carbohydrates are primarily degraded by extracellular hydrolases, and the resulting oligo-, di-, and monosaccharides are transported into the cytosol via phosphoenolpyruvate-dependent phosphotransferase systems (PTS), major facilitator superfamily, and ATP-binding cassette (ABC) transporters. In this study, a new carbohydrate utilization system of B. subtilis responsible for the utilization of alpha-galactosides of the raffinose family of oligosaccharides (RFOs) was investigated. RFOs are synthesized from sucrose in plants and are mainly found in the storage organs of plant leaves. Our results revealed the modus operandi of a new carbohydrate utilization system in B. subtilis.