Janelle N. Ruiz Assignment 2

Part II: Biochemistry

 * Question 1: What are the differences in the amino acid sequences of the proteins produced by the alleles you define in Part I? Hint: use the Compare menu to find the difference(s)between the amino acid sequences.


 * Green:Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Tyr-Trp-Arg-Gln
 * Blue:Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Tyr-Cys-Arg-Gln
 * Yellow:Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Trp-Cys-Arg-Gln
 * Red:Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Phe-Cys-Arg-Gln
 * White:Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Val-Cys-Arg-Gln

The differences in the amino acid sequences are found at position 10 and 11.

The properties of amino acid side chains make a protein pigmented as well as the sequence of the amino acids which make up the protein. How a protein is structured (i.e. its amino acid sequence) will ultimately determine how and to what degree it is able to reflect and absorb specific wavelengths of light and therefore its percieved pigment.
 * Question 2: What features of the amino acid sequence make a protein pigmented?

The differences in color between different proteins depends upon a protein's amino acid sequences as explained above. The particular pigment which is reflected by a given protein will likely be determined by the amount of and interaction between aromatic amino acid side chains. Aromatic compounds, because of the alternating double- and single-bond ring system, absorb light and are colored because of this. The size of the molecule (i.e. the amount of aromatic amino acid side chains) and the structure of the aromatic side chain (i.e. the amount and order of the double and single bond ring system) will determine the color of the protein.
 * Question 3: What features of the amino acid sequence make a protein a particular color?


 * Question 4:How do the colors combine to produce an overall color? How does this explain the genotype-phenotype rules you found in part (I)?

Because we are working under the assumption that the two proteins (allele colors) found in a diploid organism work alone as monomers rather than dimers, each protein will be reflecting and absorbing its own specific wavelength of light. When two proteins of different colors are found in a diploid organism, either one color allele will be observed in the organism or a different, new color allele will be observed. The following genotype/phenotypes were observed:


 * Green 1: green/green
 * Green 2: blue/yellow
 * Green 3: green/yellow
 * Green 4: green/blue
 * Green 5: green/white
 * Red: red
 * Red 1: white/red
 * White: white/white
 * Black: green/red
 * Purple: blue/red
 * Orange: yellow/red
 * Blue: blue/white
 * Yellow: yellow/white

Because an observed color of white indicates that all color is absorbed and non is reflected, it makes sense that a white allele would become "hidden" and therefore not observed when combined with an allele of another color. In situations where two color alleles are combined, such as with blue/red, yellow/red, and blue/yellow, genetic co-dominance is observed in which the combination of two proteins which reflect and absorb different wavelengths of light cause a new color appearing as a "blend" of the two alleles to be observed.


 * Question 5: Which proteins are found in each of the four starting organisms?

Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Tyr-Trp-Arg-Gln
 * Green:

Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Tyr-Cys-Arg-Gln
 * Blue:

Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Trp-Cys-Arg-Gln
 * Yellow:

Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Phe-Cys-Arg-Gln
 * Red:

Met-Ser-Asn-Arg-His-Ile-Leu-Leu-Val-Val-Cys-Arg-Gln
 * White:


 * Question 6: Using this knowledge, construct a purple protein.


 * Purple:

Met Ser Asn Arg His Ile Leu Leu Val Tyr Phe Cys Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Tyr Phe Arg Gln

The protein is purple because of the way in which Tyr and Phe IN THIS ORDER reflect and absorb light. Because both amino acids have aromatic side chains with alternating double and single bond ring structures, they reflect and absorb different wavelengths of light. Because the presence of Tyr tends to reflect blue light, as seen in the table below with the blue protein allele, and the presence of Phe tends to reflect red light, as seen in the table below with the red protein allele, it makes sense that the combination of the two would yeild a purple protein. Our eyes would tend to perceive the reflection of the combination of blue and red light as the color purple.

TABLE

 * White:

Met Ser Asn Arg His Ile Leu Leu Val Val Cys Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Phe Tyr Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Cys Cys Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Tyr Tyr Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Trp Tyr Arg Gln

When you add amino acids with non-aromatic side chains to these positions (10 and 11), you get a white protein. Also, though Phe and Tyr, which are amino acids with aromatic side chains, will yeild a purple protein when at postions 10 and 11, respectively, when you SWITCH Phe and Tyr, you get a white protein. Just Tyr (aromatic) and you get a white protein.


 * Orange:

Met Ser Asn Arg His Ile Leu Leu Val Phe Trp Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Trp Phe Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Trp Phe Phe Arg Gln


 * Red:

Met Ser Asn Arg His Ile Leu Leu Val Phe Phe Arg Gln

Lots of Phe at those positions gives a red protein.


 * Black:

Met Ser Asn Arg His Ile Leu Leu Val Tyr Phe Trp Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Trp Tyr Phe Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Phe Tyr Trp Arg Gln

Having all three amino acids in any combination at between positions 9 and 12 yeilds a black protein.


 * Yellow:

Met Ser Asn Arg His Ile Leu Leu Val Trp Trp Arg Gln

Met Ser Asn Arg His Ile Leu Leu Val Trp Cys Arg Gln

If many Trps are added to these positions, get a yellow protein.

Lots of Tyr (aromatic) at these positions, and you get a blue protein.
 * Blue:

It doesn’t seem to matter when you add non-aroamtic to the mix…. Stays the same color


 * Green:

Met Ser Asn Arg His Ile Leu Leu Val Tyr Trp Arg Gln

If you add a few more Tyr or Trp to these positions, get a green protein. If you switch Trp and Tyr, you get a white protein.