Saturday, January 3, 2009

Function of protein families

In inter mediary metabolism and nucleic acid metabolism account foe about 15% of the proteins represented in top proteome. Protein associated with structure and protein synthesis ,Another way to look at the proteome is to divide it in to families of proteins that carry out related functions. For example. Some proteins serve structural role some are participants in signaling pathways and other handle essential metabolic chores such as nucleic acid synthesis or carbohydrate catabolism. Based on classification by domain content and associated functional roles, Venter and colleagues estimated that division of protein functions in proteins encoded by the human genome
Enzymes involved in inter mediary metabolism and turn over (cytoskeleton proteins, ribosomal protein, chaperones, and mediators of protein degradation) account collectively for another 15%-20%. Another 20% - 35% consist of signaling proteins and DNA binding proteins. Although these numbers offer a useful perspective on how the genome is divided by protein functions, they do not tell us how much of any protein or protein class is expressed at any given time in a cell. Approximately 40% of the genome encodes protein products with on know n function. Assigning functions to these gene products represents the most fundamental challenge for human functional genomics.
Complete genomic sequences of several organisms have been completed and these data have allowed analysts to predict the products of all the organism’s genes. Moreover, based on the predicted amino acid sequences of each gene product these proteins have been classified on the basis of the domains and sequence motifs they contain.

Function of protein families

In inter mediary metabolism and nucleic acid metabolism account foe about 15% of the proteins represented in top proteome. Protein associated with structure and protein synthesis ,Another way to look at the proteome is to divide it in to families of proteins that carry out related functions. For example. Some proteins serve structural role some are participants in signaling pathways and other handle essential metabolic chores such as nucleic acid synthesis or carbohydrate catabolism. Based on classification by domain content and associated functional roles, Venter and colleagues estimated that division of protein functions in proteins encoded by the human genome
Enzymes involved in inter mediary metabolism and turn over (cytoskeleton proteins, ribosomal protein, chaperones, and mediators of protein degradation) account collectively for another 15%-20%. Another 20% - 35% consist of signaling proteins and DNA binding proteins. Although these numbers offer a useful perspective on how the genome is divided by protein functions, they do not tell us how much of any protein or protein class is expressed at any given time in a cell. Approximately 40% of the genome encodes protein products with on know n function. Assigning functions to these gene products represents the most fundamental challenge for human functional genomics.
Complete genomic sequences of several organisms have been completed and these data have allowed analysts to predict the products of all the organism’s genes. Moreover, based on the predicted amino acid sequences of each gene product these proteins have been classified on the basis of the domains and sequence motifs they contain.

Wednesday, December 31, 2008

The new biology

Proteomics is the study of the proteome, the protein complement of the genome. The terms”proteomics”and proteome” were coined by Marc Wilkins and colleagues in the early 1990s and mirror the terms “genomics” and “genome” which describe the entire collection of genes in an organism. These”-omics”terms symbolize a redefinition of how we think about biology and the working of living systems. Until the mid-1990s, biochemists, molecular biologist and cell biologists studied individual genes and proteins or small cluster of related components of specific biochemical pathways. The techniques then available – Northern blots and Western blots made charting the status of more than a handful of genes or proteins a formidable analytical task
Three developments changed the biological landscape and formed the foundation of the new biology .the first was the growth of gene, expressed sequence tag(EST), and protein – sequence data bases during the 1990s.These resources became ever more useful as practical catalogs of expressed genes in many organisms . The genome – sequencing projects of the late 1990s yielded complete genomic sequence of bacteria, yeast nematodes, and drosophila and culminated recently in the complete sequence of the human genome, sequences of plant genomes and those of other widely studied animals also are recently complete or are approaching completion. These genome- sequence databases are the catalogs from which much of our understanding of living systems eventually will be extracted.
The second key development is the introduction of use – friendly browser- based bioinformatics tools to extract information from these databases. It is now possible to search entire genomes for specific nucleic acid or protein sequences in seconds. Such database search tools are integrated with other tools and databases to predict the functions of the protein products based on the occurrence of specific functional domains or motifs.

Monday, December 29, 2008