12th Zoology

Protein structure

Protein structure

Protein are linear chains molecules made up of units called amino
acids. Approxoimately twenty different amino acids make up a protein chain.
They are called polypeptide chains as they often contain a few to several
hundred amino acids linked with each other by peptide bonds. Several
polypeptide chains form subunits for a large protein. For example the
haemoglobin consists of four subunits (Two alpha and two beta chains) each
harbouring haeme, an iron containing molecule. The peptide bond between
amino acids is fairly flexible. As a result, oligopeptide and polypeptide chains
fold to a convoluted shapes.

Every protein folds in a particular way to form a distinctive configuration for its specific function. The protein configuration is made primarily by the amino acids side chains. Some amino acid side chains are electrically charged (positive or negative). Others called polar molecules or neutral and strongly attract the electrons. A third group of amino acids are said to have non-polar or hydrophobic side chains.

Thus proteins fold up in such a way that non-polar-hydrophobic groups remain buried inside the molecule and the polar and charged groups remain outside.

The sequential and linear arrangement of amino acids in a
polypeptide represents its primary structure. The folding of protein chain to
form recognizable modules such as alpha helix and beta sheets
represents its secondary structure .

The three dimensional shape of a polypeptide is called its tertiary structure.Alpha helices and beta sheets provide further stability to protein structure.

The proteins synthesized inside a cell undergo the above mentioned
configurational changes to attain stable structures. Otherwise, they will be
digested or destroyed by the cellular proteolytic enzymes.

The proteins take up different profiles as structural and functional proteins such as enzymes and hormones etc.

In proteomics, the amino acid sequences are read by automated
sequenators and stored in computers as internationally available databases.
The information regarding three-dimensional structure of protein is stored in
another computerized database called Protein Data Bank. Only three
dimensional forms are used to define protein structure.

Protein Model (Protein structure)

In proteomics, to delineate information about a protein at atomic and
molecular levels, models are constructed. X-ray crystallography can give a
skeleton model of a protein from its results on its atomic details. With atomic
data, computers nowadays generate graphic images of the molecules on
high-resolution screen. Computer modeling of protein began as early as 1970.
The computer-generated models depict not only the properties of amino
acids in a protein but also help to understand the protein function. One of the
computer graphic models is the “Glowing coal” model.

Uses of Protein structure

1. Protein structure helps in understanding biomolecular arrangement in
tissue or cellular architecture.
2. Protein structures, protein models and computer aided graphic
models help to understand biological reactions mediated by enzymes
3. Graphic models provided by computers are valuable to predict which
fragments of a medically important protein can be used to design drugs and
4. Proteomics also helps in chemical industries to manufacture drugs, various
chemical compounds and enzymes.


Related Topics in Zoology:

Bio Zoology All Important Topics

  1. MODERN GENETICS Introduction and Scope

  2. Human Genetics – Karyotyping

  3. Karyotyping of Human chromosomes

  4. Genetic Engineering

  5. Tools Of Genetic Engineering

  6. Restriction enzymes – Recombinant DNA Technology

  7. DNA – Segmenting / Fragmenting

  8. Genetic Diseases

  9. Human Genome Project (HGP)

  10. Cloning

  11. Transgenic organisms

  12. Gene Therapy

  13. Bioinformatics

  14. Scope of Genetic Engineering – Scope of Bioinformatics

  15. Database

  16. Genome sequencing

  17. Protein structure


    1. Human population and explosion

    2. Population Explosion

    3. Growing Population and Environmental impacts

    4. Global warming – Green house effect

    5. Ozone layer depletion

    6. Prevention and Effect of Ozone depletions

    7. Waste management – Classification

    8. Management of hazardous wastes

    9. Management of non hazardous wastes

    10. Waste water treatment and management

    11. Biodiversity

    12. Conservation of Biodiversity

    13. Characteristics of a Bioreserve

    14. Energy crisis and its environmental impact

    15. Steps to be taken to resolve energy crisis

    16. Environmental impacts of Power Sources

    17. Poverty and environment

    18. Fresh water crisis and management

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