Revision as of 23:52, 27 October 2020

bcsA-Bacterial Cellulose Synthase A

This part codes for the BscA protein, the catalytic subunit which synthesizes cellulose in Bacteria.

Description

BcsA forms the transmembrane pore across the inner membrane. BcsA, together with the periplasmic membrane-anchored BcsB subunit, forms a complex that is sufficient for cellulose synthesis in vitro. This CDS originates from a very productive cellulose synthesising bacterium, Komagataeibacter xylinus (GenBank Acc. No. X54676.1). It is the catalytically acitve subunit of the bacterial Cellulose Synthetase.

Protein Analysis

BcsA is homologous to eukaryotic cellulose synthases and contains eight transmembrane helices and a cytosolic glycotransferase domain between transmembrane helices four and five. BcsA also forms a polysaccharide channel across the membrane, directly above the active site, thereby allowing the coupling of cellulose synthesis and translocation. In addition, BcsA forms a PilZ domain within its C-terminal intracellular extension, which consists of a six-stranded ß-barrel and a preceding linker region. The ß-barrel rests against the intracellular glycotransferase domain and is connected to BcsA’s C-terminal transmembrane helix.

The Bacterial Bcs Operon

The putative operon consists of four genes, bcsA, bcsB, bcsC and bcsD. It encodes membrane-associated proteins can catalyse extracellular Bacterial Cellulose synthesis in vivo. Once the bcsABCD operon expression is triggered, BcsA and BcsB proteins form the BcsAB complex, which binds its substrate, UDP-glucose, at an intracellular glycosyltransferase (GT) domain. This complec is the active core of the cellulose synthase. This is followed by the secretion of BC fibres through pores and passageways formed by BcsC and BcsD proteins. Co expression with Cmcax and CcpAx have shown increased production. The cellulose synthase, BcsC, BcsD, Cmcax, and CcpAx are the biocatalysts of UDP-glucose transformation to cellulose. Two main applications of cellulose in biosciences are scaffolds for tissue engineering and generally in biomedicine.

SOURCE OF THIS PART

The nucleotide sequences of the bacterial cellulose operon come from the strain Komagataeibacter xylinus and GenBank database (Acc.No.X54676.1). K.xylinus is a member of the acetic acid bacteria, a group of Gram-negative aerobic bacteria that produce acetic acid during fermentation.

Useful Links:

NCBI taxonomy:

https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=28448&lvl=3&lin=f&keep=1&srchmode=1&unlock

GenBank link:

https://www.ncbi.nlm.nih.gov/nuccore/X54676.1

Codon optimisation bank:

http://genomes.urv.es/OPTIMIZER/?fbclid=IwAR0ALbP_C8UVY4itvYdNX8b5KYYUM5ulQojz8UJAK6Zj5llobNNxE-jYmXQ

Codon optimization table:

https://www.kazusa.or.jp/codon/cgi-bin/showcodon.cgi?species=376686&fbclid=IwAR0gwwrIarZsiYhWvHPc2BKy-iB_2OM-DPB5I2HYJZwBNiasmlLXWK87PwM

REFERENCES

Braun, T., Khubbar, M., Saffarini, D., & McBride, M. (2005). Flavobacterium johnsoniae Gliding Motility Genes Identified by mariner Mutagenesis. Journal Of Bacteriology, 187(20), 6943-6952. doi: 10.1128/jb.187.20.6943-6952.2005

Buldum, G., Bismarck, A., & Mantalaris, A. (2017). Recombinant biosynthesis of bacterial cellulose in genetically modified Escherichia coli. Bioprocess And Biosystems Engineering, 41(2), 265-279. doi: 10.1007/s00449-017-1864-1

Johansen, V., Catón, L., Hamidjaja, R., Oosterink, E., Wilts, B., & Rasmussen, T. et al. (2018). Genetic manipulation of structural color in bacterial colonies. Proceedings Of The National Academy Of Sciences, 115(11), 2652-2657. doi: 10.1073/pnas.1716214115

McBride, M., & Kempf, M. (1996). Development of techniques for the genetic manipulation of the gliding bacterium Cytophaga johnsonae. Journal Of Bacteriology, 178(3), 583-590. doi: 10.1128/jb.178.3.583-590.1996

Nakamura, Y. (2000). Codon usage tabulated from international DNA sequence databases: status for the year 2000. Nucleic Acids Research, 28(1), 292-292. doi: 10.1093/nar/28.1.292

Omadjela, O., Narahari, A., Strumillo, J., Melida, H., Mazur, O., Bulone, V., & Zimmer, J. (2013). BcsA and BcsB form the catalytically active core of bacterial cellulose synthase sufficient for in vitro cellulose synthesis. Proceedings Of The National Academy Of Sciences, 110(44), 17856-17861. doi: 10.1073/pnas.1314063110

Römling, U., & Galperin, M. (2015). Bacterial cellulose biosynthesis: diversity of operons, subunits, products, and functions. Trends In Microbiology, 23(9), 545-557. doi: 10.1016/j.tim.2015.05.005