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G C Cannon

Publications and source records attributed to G C Cannon.

6 recordsLinked to original sources
PubMed1991

In situ assay of ribulose-1,5-bisphosphate carboxylase/oxygenase in Thiobacillus neapolitanus.

Cells permeabilized with chloroform yielded ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activities nearly equal to those of cell extracts, thus indicating that both cytoplasmic and carboxysomal RuBisCO are functional in situ. The carboxysomal and cytoplasmic RuBisCO both form the CO2-Mg2(+)-enzyme ternary complex, as evidenced by stabilization with 2-C-carboxy-D-arabinitol-1,5-bisphosphate (CABP), a potent competitive inhibitor of RuBisCO. The data are consistent with the hypothesis that the carboxysome is functional in carbon dioxide fixation.

Plant Proteins↗
PubMed1990

Purification and characterization of a DNA polymerase from the cyanobacterium Anacystis nidulans R2.

A DNA polymerase has been highly purified from Anacystis nidulans R2. Electrophoretic analysis in sodium dodecyl sulfate-polyacrylamide gels revealed that the final fraction contains three bands of Mr 107,000, 93,000, and 51,000, respectively. Analysis of purified DNA polymerase activity in situ indicates that of the three polypeptides the Mr 107,000 species has the catalytic activities. The native molecular weight of the enzyme was estimated by glycerol gradient sedimentation to be 100,000. The enzyme has an absolute requirement for a divalent cation. Mg2+ can be replaced with Mn2+, but the DNA polymerase is less active. Potassium chloride stimulates the enzyme, while potassium phosphate has no apparent effect. The enzyme is active over a pH range from 7.5 to 9.5 in 50mM Tris-HCl buffer. The ability of the cyanobacterial DNA polymerase to use activated DNA as a template, its associated 3'----5' and 5'----3' exonuclease activities, as well as its resistance to N-ethylmaleimide, dideoxynucleotides, arabinosyl-CTP and aphidicolin suggest a similarity between this enzyme and E. coli DNA polymerase I. This is the first characterization of a DNA polymerase from a cyanobacterium.

Cyanobacteria↗
PubMed1990

Partial purification and characterization of a DNA helicase from chloroplasts of Glycine max.

A DNA helicase activity was detected in extracts of purified chloroplasts from the SB-1 cell line of Glycine max and partially purified by column chromatography on DEAE cellulose, phosphocellulose, and single-stranded DNA cellulose. The chloroplast helicase has a DNA-dependent ATPase activity, and its strand displacement activity is strictly dependent upon the presence of a nucleoside triphosphate and Mg2+ or Mn2+. Strand displacement activity does not require a free unannealed single-strand or replication fork-like structure.

Adenosine Triphosphatases↗
PubMed1987

Sequence analysis on microcomputers.

Overall, each of the program packages performed their tasks satisfactorily. For analyses where there was a well-defined answer, such as a search for a restriction site, there were few significant differences between the program sets. However, for tasks in which a degree of flexibility is desirable, such as homology or similarity determinations and database searches, DNASTAR consistently afforded the user more options in conducting the required analysis than did the other two packages. However, for laboratories where sequence analysis is not a major effort and the expense of a full sequence analysis workstation cannot be justified, MicroGenie and IBI-Pustell offer a satisfactory alternative. MicroGenie is a polished program system. Many may find that its user interface is more "user friendly" than the standard menu-driven interfaces. Its system of filing sequences under individual passwords facilitates use by more than one person. MicroGenie uses a hardware device for software protection that occupies a card slot in the computer on which it is used. Although I am sympathetic to the problem of software piracy, I feel that a less drastic solution is in order for a program likely to be sharing limited computer space with other software packages. The IBI-Pustell package performs the required analysis functions as accurately and quickly as MicroGenie but it lacks the clearness and ease of use. The menu system seems disjointed, and new or infrequent users often find themselves at apparent "dead-end menus" where the only clear alternative is to restart the entire program package. It is suggested from published accounts that the user interface is going to be upgraded and perhaps when that version is available, use of the system will be improved. The documentation accompanying each package was relatively clear as to how to run the programs, but all three packages assumed that the user was familiar with the computational techniques employed. MicroGenie and IBI-Pustell further complicated their documentation by mixing instructions for the version based on floppy disk operation with that for the hard disk version.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1977

Icosahedral inclusions (carboxysomes) of Nitrobacter agilis.

The icosahedral bodies of Nitrobacter agilis are about 120 nm in diameter and, as viewed by electron microscopy, consist of an outer shell enclosing 10-nm particles. The inner 10-nm particle is the enzyme D-ribulose 1,5-bisphosphate carboxylase. The bodies isolated from cells incubated 1 month without nitrite had a specific activity for the enzyme of 0.54 mu mol of CO2 fixed per min per mg of protein.

Carbon Dioxide↗