Difference between revisions of "Part:BBa K2559000"

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Bacterial cellulose synthase Z (BcsZ)

The BBa_K2559000 is an endoglucanase (Bcs Z) involved in the process of cellulose hydrolysis, and its roles in cellulose biosynthesis have long remained obscure.

Usage and Biology

Bacterial cellulose synthase Z (BCSZ) from several bacteria have an endo-β-1,4-glucanase (cellulase) activity, and E. coli protein was even crystallized in a complex with the substrate cellopentaose, and we believe its however, the roles in cellulose biosynthesis remained obscure.[1]

Figure 1 BcsZ adopts an (α/α)6-barrel fold. BcsZ is shown as a cartoon from a top (A) and side (B) view. The inner and outer helices are shown in dark and pale green, respectively, and the three β-sheets flanking the substrate binding cleft are shown in blue. The catalytic residues Glu55 and Asp243 are shown as red sticks. Helices are labeled H1–H12 from the N to the C terminus. The C-terminal residues 349–357 of BcsZ form a two-stranded β-sheet (colored orange) on the opposite side of the substrate binding pocket.[2]

Degradation of CMC by BcsZ

The BcsZ in E. coli was even crystallized in a complex with the substrate cellopentaose.When BcsZ-overexpressing E. coli cells were grown on agar plates containing 2% CMC, a clear halo appeared around the colonies after staining with Congo Red.Purified cellulase from Aspergillus niger (Tokyo Chemical Industry, GenBank entry CAA03658.1) and bovine serum albumin served as positive and negative controls, respectively.[2]

Figure 2 The right show degradation of CMC by BcsZ which indicate the cellulase activity of BcsZ in E.coli.

We introduced bcsZ, H, A, B, C, D, bglX from the Acetobacter xylinum which involve in the process of bacterial cellulose synthesis into the model organism cyanobacteria (Synechocystis sp.pcc6803),and we obtain the transgenic cyanobacteria.

Transgenic cyanobacteria with bcsZH-ABCD-bglX genes and the cellulose measurement

Measurement of cyanobacteria glucose (3 repeats). The same of amount of transgenic cyanobacteria with bcsZH-ABCD-bglX genes and wild-type were treated with lysozyme to break the cells. Due to lacking a direct way to measure the content of cellu;ose in bacterial cell wall. Therefore, glucose can be used as an alternative parameter for measuring the content of cellulose since it can be digested into glucose by cellulose. The differences between the red colum and blue column indicated that the content of bacteria cellulose.

Figure 3 The measurement of cellulose content in transgenic cyanobacteria which expressed bcs gene . The P-value verified that the distinction between treatment group  and control group.

The part is facilitate the in-depth research for other teams!

Reference :

1.Romling U & Galperin MY (Bacterial cellulose biosynthesis: diversity of operons, subunits, products, and functions. (Translated from eng) Trends Microbiol 23(9):545-557 (in eng).

2.Mazur O & Zimmer J (Apo- and cellopentaose-bound structures of the bacterial cellulose synthase subunit BcsZ. (Translated from eng) J Biol Chem 286(20):17601-17606 (in eng).

Sequence and Features