Proteins I
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Proteins I
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introduction to proteins
- Lecture number:
- 2
- Pages:
- 2
- Type:
- Lecture Note
- School:
- University of North Texas
- Course:
- Biol 3510 - Cell Biology
- Edition:
- 1
Unformatted text preview:
BIOL 3510 1st Edition Lecture 2 Outline of Last Lecture I Introduction to cells II Microscopy III Prokaryotes and Eukaryotes IV Model Organisms Outline of Current Lecture I Introduction to proteins II Types of Non Covalent Bonds Forces III Protein structures IV Measuring Protein Current Lecture Proteins are composed of chains of amino acids linked together by peptide bonds Amino acids can be grouped by their side chains Peptide bonds are covalent bonds 90 kcal mol in water or vacuum where electrons are shared shared unequally in a polar covalent bond Polar covalent bonds create dipoles within a molecule due to unequal electron distribution Peptide bonds form via condensation reactions The conformation of a protein is specified by its amino acid sequence 3D shape is inherent 4 levels of protein structural organization primary secondary tertiary quaternary 4 Types of Non Covalent Bonds Forces in Cells 1 Electrostatic attractions 3kcal mol forces that attract oppositely charged atoms 2 Hydrogen bonds 1kcal mol a weak bond between an electronegative atom and a hydrogen bound to another electronegative atom 3 Van der Waals interactions 0 1 kcal mol fluctuations in the electron cloud surrounding an atom creates a transient dipole This dipole induces an opposing dipole in a nearby atom generating an attraction 4 Hydrophobic forces not really a bond exclusion of non polar surfaces from the hydrogen bonded water network These non covalent bonds forces stabilize the 3D conformations of proteins These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Chaperones are proteins that improve the efficiency of protein folding in cells Hydrogen bonds between polypeptide backbone groups create secondary structures Alpha helix Polypeptide twists to form a cylinder Stabilized by H bonds between a C O n and a N H n 3 Often found in proteins that span membranes 2 or 3 of them wrapped around
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