Directions: Look at the following amino-acid sequences from two warm-water species and one cold-water

species and identify where changes in the sequence occurred. 

Line 1: C. punctipinnis:Temperate (cold-adapted)

Line 2: C. caudalis:Tropical(warm-adapted)

Line 3: C. xanthochira: Tropical (warm-adapted)

151

GFERHRVIGS  GTNLDSARFR HIMGEKLHLH PSSCHGWIVG  EHDGSSVPVW

GFERHRVIGS  GTNLDSARFR HIMGEKLHLH PSSCHGWIVG  EHDGSSVPVW

GFERHRVIGS  GTNLDSARFR HIMGEKLHLH PSSCHGWIIG   EHDGSSVPVW

201

SGVNVAGVSL  QGLNPQMGTD GDSEKWKEVH KLVVDGAYEV   IKLKGYTSWA

SGVNVAGVSL  QALNPQMGAE GDSENWKAVH KQVVDGAYEV  IKLKGYTSWA

SGVNVAGVSL  QGLNPKMGAE GDSENWKEVH KLVVDGAYEV   IKLKGYTSWA

251

IGMSVADLVE  SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV  PCVLGNSGLT

IGMSVADLVE  SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV  PCVLGNSGLT

IGMSVADLVE  SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV  PCVLGNSGLT

301

DVIHMTLKPE  EEKQLVKSAE TLWGVQKELT

DVIHMTLKPD  EEKVLVKSAE TLWGVQKELT

DVIHMTLKPD  EEKQLVKSAE TLWGVQKELT

Which amino acids changed between the three species?  List four of them below, using the number of the amino acid.

            Example: Amino acid 189 changed from valine to isoleucine in a warm adapted species. 

1) _______________________________________________________________

2) _______________________________________________________________

3) _______________________________________________________________

4) _______________________________________________________________

2. What were the changes in the chemical properties of the R-groups? Use the amino-acid chart to in the Powerpoint file to answer this question.

            Example: Both valine and isoleucine are nonpolar. 

1) _______________________________________________________________

2) _______________________________________________________________

3) _______________________________________________________________

4) _______________________________________________________________

3. How might the changes that you identified affect the protein’s structure?

Example: The change would likely have no effect. Neither valine and isoleucine would promote hydrogen bonding with water, because their R groups are nonpolar and thus hydrophobic.

1) _______________________________________________________________

2) _______________________________________________________________

3) _______________________________________________________________

4) _______________________________________________________________

4. Assuming that the mutations are adaptive, how should the changes that you identified affect the stability of the protein at low and high temperatures?

 

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