Clusters of Orthologous Groups (COGs)

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Clusters of Orthologous Groups (COGs)
Who:	NCBI
What:	Phylogenetic classification of proteins encoded in complete genomes
Where:	Clusters of Orthologous Groups (COGs)
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About Clusters of Orthologous Groups (COGs)

The Clusters of Orthologous Groups (COGs) of proteins were generated by comparing the protein sequences of complete genomes. Each cluster contains proteins or groups of paralogs from at least three lineages. The current COG database contains both prokaryotic and eukaryotic clusters.

Content

The COGs database contains Clusters from both Unicellular and Eukaryotic Organisms. There are currently 66 Unicellular organisms and can be found here. The eukaryotic organisms are limited to seven organisms: Arabidopsis thaliana, Caenorhabditis elegans, Drosophilia melanogaster, Homo Sapiens, Saccharomyces cerevisiae, Schizosaccharomyces pombe and Encephalitozoon cuniculi.

The following statistics come from Tatusov RL et al (2003).

The COG collection consists of 138,458 proteins from 66 genomes. These proteins form 4873 COGs. Unfortunatly, these COGs are not available on the website. Howewver, a subset are available from the initial version. The KOG sets contain 4,852 clusters of orthologs, utilizing 59,838 proteins. This is approximately 54% of the analyzed eukaryotic gene products.

Categories The COGs and KOGs are classified into functional classifications. The functional categories are not listed on the newe version of the COG website. They are designated in the paper and listed below for reference.

A	RNA processing and modification
B	Chromatin Structure and dynamics
C	Energy production and conversion
D	Cell cycle control and mitosis
E	Amino Acid metabolis and transport
F	Nucleotide metabolism and transport
G	Carbohydrate metabolism and transport
H	Coenzyme metabolis
I	Lipid metabolism
J	Tranlsation
K	Transcription
L	Replication and repair
M	Cell wall/membrane/envelop biogenesis
N	Cell motility
O	Post-translational modification, protein turnover, chaperone functions
P	Inorganic ion transport and metabolism
Q	Secondary Structure
T	Signal Transduction
U	Intracellular trafficing and secretion
Y	Nuclear structure
Z	Cytoskeleton
R	General Functional Prediction only
S	Function Unknown	} Using Clusters of Orthologous Groups (COGs) Browsing Searching Usage examples Add links to additional pages describing success stories here. Other sites with related content Technology Web Services/API Discussion References The COG database: an updated version includes eukaryotes. Tatusov RL et al BMC Bioinformatics. 2003 Sep 11;4:41. Epub 2003 Sep 11. Full Text The COG database: a tool for genome-scale analysis of protein functions and evolution. Tatusov RL et al Nucleic Acids Res. 2000 Jan 1;28(1):33-6. Full Text A genomic perspective on protein families. Tatusov RL et al Science. 1997 Oct 24;278(5338):631-7.Abstract External Links Clusters of Orthologous Groups (COGs) Discussion of Clusters of Orthologous Groups (COGs) on other websites