Cellulomonas fimi cellulases

Gilkes, NR Warren, RA Miller, RC Kilburn, DG. Precise excision of the cellulose binding domains from two Cellulomonas fimi cellulases by a homologous protease and the effect on catalysis. The Journal of Biological Chewistry, 1988, 263(21), 10401-7. 

Cellulomonas fimi Endoglucanase A (i7) Microbispora bispora Endoglucanase I (5) Streptomyces sp. Cellulase A (72) Trichoderma reesei Cellobiohydrolase II (75)... 

Langsford et al. reported that Cellulomonas fimi culture supernatants contained cellulase and proteinase activities, for which there appeared to be a relationship. Glucose repressed the synthesis of both activities and cellulose induced both 60), Adding cellulose to Cellulomonas sp. (NRCC 2406) cultures stimulated growth and improved production of cellulases 61). Optimum conditions for growth and cellulase production were pH 6.5 and 30 C. The addition of glucose in the presence of cellulose inhibited growth. Several species of Cellulomonas have cellobiose phosphorylase. 

The core-enzymes, prepared in our laboratory, and containing the active centers, were successfully crystallized (Dr. Jones, Uppsala, communicated) and tertiary structures will be described in the near future. Chemical modification studies on these enzymes are currently being undertaken in our laboratory identification of important catalytic residues and location of the active centers will lead to more functional information on these enzymes. Other cellulases such as some endoglucanases from Clostridium thermocel-lum (EG A, EG B, EG D) (10) and EngA and Exg from Cellulomonas fimi (19) also contain sequences of conserved, terminally located and sometimes reiterated, amino acids. Some of these sequences are preceded by proline-serine rich domains. Thus, a bistructural-bifunctional organization seems to be a rather common feature among cellulases, at least for EngA and Exg from C. fimi and the enzymes from Trichoderma reesei. 

Tull D, Withers SG (1994) Mechanisms of cellulases and xylanases a detailed kinetic study of the exo-beta-1, 4-glucanase from Cellulomonas fimi. Biochemistry 33 6363-6370... 

T. reesei, TC, Humicola insolens, EGV, EGV-core Cellulomonas fimi, CenA-core Staining levels, effect of mechanical action Cellulases without CBDs and mechanical action caused less backstaining... 

Figure 1. The organization of catalytic and non-catalytic domains in cellulases from C. fimi and other bacteria. CfCenA, B and C, and CfCex are the endo- and exo-p- 1, 4-glucanases of C. fimi, ClfX is a translated open reading frame from Cellulomonas flavigena (29), CtEGD and PfEndA are endo-p-1, 4-glucanases from Clostridium thermocellum and Pseudomonas fluorescens, respectively (30,31), The primary structures are drawn approximately to scale and are numbered from the amino terminus of the mature protein ClfX is numbered from the start of the open reading frame. Unshaded areas represent catalytic domains, cross-hatched areas indicate cellulose-binding domains, repeated blocks of amino acids are stippled, and black areas represent linker regions.

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