Proteins and Amino Acids Vishal Patel CHEM 504 Biochemistry

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Proteins and Amino Acids

• Vishal Patel
• CHEM 504 Biochemistry
• Dr. E. Thornton

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Proteins

• provide structure, catalyze cellular reactions
  and carry out other tasks.
• have multiple biological functions
• classified according to their biological roles.

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Types of proteins and their function

• Enzymes
• Most varied and specialized proteins with
  catalytic activity.
• All chemical reactions of organic biomolecules in
  cells are catalyzed by enzymes.

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Types of proteins and their function

• Transport Proteins
• Bind and carry molecules or ions to organs in the
  blood plasma.
• Lipoproteins in blood plasma carries lipids from
  the live to other organs.

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Types of proteins and their function

• Nutrient and Storage Proteins
• Seeds of many plants store nutrient proteins
  required for the growth of the germinating
  seedlings.
• Ovalbumin, the major protein of egg white, and
  casein the major protein of milk are examples of
  nutrient proteins.

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Types of proteins and their function

• Contractile or Motile Proteins
• Some proteins endow cells and organisms with the
  ability to contract, to change shape, or to move
  about.
• Tubulin is the protein from which microtubules
  are built.

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Types of proteins and their function

• Structural Proteins
• Many proteins serve as supporting filaments,
  cables, or sheets, to give biological structures
  strength or protection.
• Major component of tendons and cartilage is the
  fibrous protein collagen, which has very high
  tensile strength.
• Ligaments contain elastin, a structural protein.

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Types of proteins and their function

• Defense Proteins
• Defend organisms against invasion by other
  species or protect them
• Immunoglobulin or antibodies, are made by the
  lymphocytes of vertebrates and can recognize
  precipitate or neutralize invading bacteria
• Fibrinogen and thrombin are blood clotting
  proteins

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Types of proteins and their function

• Regulatory Proteins
• Help regulate cellular or physiological activity.
• The cellular response to many hormonal signals is
  often mediated by a class of GTP-binding proteins
  called G proteins.

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Amino Acids Building Blocks of Proteins

• Every amino acid has the same fundamental
  structure which consists of a central carbon
  bonded to an amino group, a carboxyl group a
  hydrogen atom.

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Example of an Amino Group
R Group
Carboxyl Group
Amino Group
Central Carbon
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Amino Acids Side Groups

• There are 20 different types of amino acids used
  in making proteins.
• (You will have a change to study them
  interactively on the WWW.)
• The essential structure is the same in all 20
  molecules.
• The 20 molecules differ in the side groups.

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Amino Acids Building Blocks of Proteins

• A peptide bond is a covalent bond formed.
• Polypeptides are polymers of amino acids linked
  together by peptide bonds, with the amino group
  of one acid joining the carboxyl groups of its
  neighbor.

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Amino Acids Building Blocks of Proteins
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Amino Acids Building Blocks of Proteins

• The peptide bond is formed when the OH group from
  the carboxyl group of one of the amino acids is
  removed and a hydrogen from the other amino acid
  is removed. The OH and H bond to from water.
• The formation of water from the two amino acids
  is called dehydration synthesis.
• The covalent linkage that is formed is known as a
  peptide bond, and the molecule that is formed by
  the linking of amino acids is called polypeptide.
  

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Proteins are Very Large Molecules

• Some proteins consist of a single polypeptide
  chain and others called multisubunit proteins,
  have two or more.
• Individual polypeptide chains in a multisubunit
  protein may be identical or different. If at
  least some are identical, the protein is
  sometimes called an oligomers protein and the
  subunits themselves are referred to as protomers.

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Levels of Protein Organization

• Primary Structure
• Secondary Structure
• Tertiary Structure
• Quaternary structure

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Levels of Protein Organization
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Primary Structure

• Covalent bonds between amino acids and is
  normally defined by the sequence of
  peptide-bonded amino acids and locations of
  disulfide bonds.
• The relative spatial arrangement of the linked
  amino acids is unspecified.

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Secondary Structure

• Refers to regular recurring arrangements in space
  of adjacent amino acid residues in a polypeptide
  chain.
• There are few common types of secondary
  structure, the most prominent being the a helix
  ß conformation.

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Tertiary Structure

• The spatial relationship among all amino acids in
  a polypeptide.
• It is the complete 3D structure of the
  polypeptide.

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Quaternary Structure

• Proteins with several polypeptide chains have one
  more level of structure referred to at the
  quaternary structure.
• Refers to the spatial relationship of the
  polypeptides, or subunits, within the protein

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Lets sing the protein song.

• O Little Protein Molecule (Song)

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Independent Practice

• Go to http//biology.clc.uc.edu/courses/bio104/pro
  tein.htm
• Find and make note of the different types of
  amino acids used in making proteins.

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References

• http//www.beldem.com/library/showimg.asp?tabBELC
  ategoryfldCatIDval1
• http//images.google.com/imgres?imgurlhttp//www.
  wisc.edu/molpharm/faculty/ruoho/ruohopic.jpgimgre
  furlhttp//www.wisc.edu/molpharm/faculty/ruoho.ht
  mlh349w385sz29hlenstart18sig2tsc5tpZFN
  pqxV0Xvrt0LMQtbnidfXR8rbT7iBI-MMtbnh111tbnw
  123ei8FyFRrSaLpuYeMK57PMBprev/images3Fq3Dtra
  nsport2Bproteins26gbv3D226svnum3D1026hl3Den
  
• http//www.wisc.edu/molpharm/faculty/ruoho/ruohopi
  c.jpg
• http//www.lbl.gov/images/PID/dimer.jpg
• http//www.theochem.ruhr-uni-bochum.de/axel.kohlm
  eyer/pics/elastin-closed-solv-shell.png
• http//www-nmr.cabm.rutgers.edu/photogallery/prote
  ins/gif/kst1.gif
• http//images.google.com/imgres?imgurlhttp//www.
  msg.ucsf.edu/flett/Images_folder/actin.jpgimgrefu
  rlhttp//www.msg.ucsf.edu/flett/Support2.htmlh5
  00w500sz121hlenstart16sig2vsTTR5xfCfTKSE
  MnVG_i8gtbnidWJshzEV1qBSXNMtbnh130tbnw130e
  i2GKFRrqOGZuWeOXzxPMBprev/images3Fq3Dregulato
  ry2Bproteins26gbv3D226svnum3D1026hl3Den
• http//images.google.com/imgres?imgurlhttp//acad
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  uny.edu/biology/bio4fv/page/3d_prot.htmh1142w5
  85sz537hlenstart2tbnid4gntmshkMPL0BMtbnh
  150tbnw77prev/images3Fq3DPrimary2BStructur
  e2Bof2Ba2BProtein26gbv3D226svnum3D1026hl3
  Den26sa3DG