Conservative Amino Acid Substations in Proteins Flashcards Preview

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Flashcards in Conservative Amino Acid Substations in Proteins Deck (18):
1

How we use our knowledge of amino acid structure in genetics

- important in genomic sequencing an analysis
- function and evolution of proteins due to comparative sequences of nucleic acids to deduce sequences of proteins.

2

Conservative

unlikely to result in major change of the characteristics of a protein.

3

Acidic R group conservations

- Asp (D) and Glu (E)

4

Basic R group conservations

- Lys (K), Arg (R), and His (H)

5

Hydrophobic R group conservations

- Leu (L), Ile (I), Val (V)
- about the same size

6

Amide R group conservations

- Asn (N) and Gln (Q)

7

Aromatic group conservations

- Phe (F), Tyr (Y), and Trp (W)

8

Conservation on a genetic basis

- Many (but not all) amino substations that are conservative on a structural basis and also conservative on a genetic basis.
- They can result from the change of a single nucleotide in the third position of the codon.

9

Conservation on a genetic basis example

- Asp (D) GA U/C
- Glu (E) GA A/G

10

Aligning conserved sequences

- clone
- sequence
- BLAST
- align with CLUSTAL

11

BLAST

- find homology of protein
- determine hypothetical gene or actual gene

12

DNA polymerases

- proofread

13

Taq polymerases

- makes more mistakes
- fidelity

14

conservative substations on the frequency of substitution basis

- if one AA substitutes for another at a frequency higher than expected by chance = conservative
- determined statistically

15

BLAST

peptide or nucleic acid sequence and want to find what known proteins or nucleic acids have the sequence or related sequences.

16

CLUSTAL

- 2 or more proteins or nucleic acid sequences and you want to align them with the best fit.

17

strongly conserved versus structurally conserved substitutions

- are the same but 5 additional indications of homology in weakly conserved substitutions

18

Effect of non-conservative amino acid substitutions

- Normal erythrocytes versus sickle-cell anemia erythrocytes
- a homozygous mutation that changes Glutamic Acid (a very hydrophilic amino acid) to Valine (a very hydrophobic amino acid)