Lecture 5 - 3-D Structure of Proteins Flashcards

1
Q

What is responsible for hydrogen bonding within proteins?

A

-Amino groups (NH3) -Carbonyl groups (COOH)

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2
Q

The carbons of an AA that lie on either side of the chiral carbon

A

alpha-Carbon

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3
Q

Alpha-carbons are on same side of the amino acid

A

Cis

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4
Q

Alpha-carbons on opposite side of the amino acid

A

Trans

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5
Q

Bond between Nitrogen and chiral carbon

A

phi

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6
Q

Bond between chiral carbon and carboxylic acid group

A

psi

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7
Q

Linear arrangement of AA residues

A

primary structure

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8
Q

Coiling and/or pleating of amino acid chain

A

secondary structure

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9
Q

Alpha helices work to stabilize proteins by _____

A

Hydrogen bonds

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10
Q

Number of amino acids per turn in alpha helix

A

3.6

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11
Q

In beta strands, when one AA hydrogen bonds with only one other AA, it is a (parallel/anti-parallel).

A

Anti-parallel

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12
Q

In beta strands, when one AA residue hydrogen bonds to two other AA residues, it is (parallel/anti-parallel)

A

parallel

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13
Q

Specific 3-D configuration of a peptide chain

A

Tertiary structure

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14
Q

Bonding between cystiene residues, works to stabilize proteins by covalent linkage

A

Di-sulfide bonds

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15
Q

The structure of most “structural proteins”

A

Filamentous (F-proteins)

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16
Q

The structure of most enzymes

A

Globular (G-proteins)

17
Q

Multiple subunit proteins coming together, often after post-translational modification

A

Quaternary structure

18
Q

How are subunits held together in quaternary structure???

A

NON-covalent linkages!!!!

19
Q

What is the repeating motif in collagen?

A

-Gly-X-Y-Gly-X-Y-

20
Q

Why is repeating Gly in collagen important?

A

Allow for small, tight protein turns; it can be compacted

21
Q

Clinical correlation: what is the mechanism behind “scurvy?”

A

A defective Proline hydroxylase prevents -OH from being added to Proline, this produces the inability to form collagen, which results in poor wound healing/destroyed connective tissue

22
Q

Breaking of disulfide bonds

A

protein denaturation

23
Q

What are the steps of protein denaturation?

A

Increased heat produces most of the denaturation; chemical denaturation breaks di-sulfide bonds

24
Q

What are the three main denaturing agents?

A
  • Urea - Beta-mercaptoethanol - Guanidinium chloride
25
Q

The ____ of a protein is formed by the amino/carbonyl connection, with side chains projecting off.

A

backbone

26
Q

2* structure bonding

A

α−helix and β−turn/β−sheets

27
Q

3* structure bonding

A

-S-S- bonding

H-bonding

metal binding

hydrophobic interaction