Introduction to protein structure Flashcards Preview

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Flashcards in Introduction to protein structure Deck (10)
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Sketch a  two amino acids linked with a peptide bond and identify the amino terminus, carboxyl terminus and side chains

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Define Primary Sequence

is the linear sequence of amino acids that make up the proteins


Define secondary structure

Secondary structure is the folding of the polypeptide chain due to hydrogen bonding into an alpha helix structure, resembling a coiled spring, or a beta pleated sheet.


Define tertiary structure

The final 3D structure of a protein, entailing the shaping of a secondary structure.


Define quanternary structure

Is the 3D structure of a multimeric protein composed of several subunits (polypeptide chains).


Draw an alpha helix

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What happens when proline is added to a polypeptide chain

When proline is joined to a polypeptide chain, the NH group of the amino acid is lost. This prevents the side chain from hydrogen bonding with C=O groups of another residue within the helix, thereby distorting the helical conformation, putting a ‘kink’ into it


Draw a beta pleated sheet

add pic In the b-pleated sheet, the NH and C=O groups point out at right angles to the line of the backbone. This almost two dimensional sheet is pleated, like the bellows of an accordion


What type of bond stabalises beta pleated sheet and alpha helix

Hydrogen bonds


Name the bonds that hold proteins together




Van der Waals Forces

Hydrophobic Interactions

Usually hydrophobic side chains are packed in the interior. This creates a hydrophobic core and a hydrophiic surface to most proteins