Lecture 30 Protein Synthesis and Protein Functions Flashcards
Amino acids
- primary structure of a protein
- grouped by side chain (charged, uncharged polar, or non polar)
- side chain is important for function, and restrict rotation around the alpha carbon in terms of what type of confirmation you can achieve
Secondary structure
-secondary structure refers to the stretches of the polypeptide chain that form alpha helices or b sheets
B sheets
- parallel
- or anti parallel
What determines the rotation of the amino acid?
- the type of side chai (can have profound effect on structure and function)
Tertiary structure
- full 3D structure of protein
- globular, or linear, rod shaped etc.
Quaternary structure
- used for proteins that have multiple polypeptide chains that make them up
LRP5 HBM mutation
- glycine substituted for valine at 171
- changes ability of protein to interact with certain regulator of LRP5 and prevent inhibition of LRP5 pathway
Protein motifs
- shared sequences of amino acids that can be used to identify potential members of a protein family
- shared motifs generally equate to similar functions
Protein domains
- structural entities that function essentially independently within a protein and can be built form a specific motif or set of motifs
- beta propellor domains
YWT on LRP5
- motif (4 of them)
EGF
- motif on LRP5
LDL receptor
- motif on LRP5
Types of protein sequence motifs
- Proteolytic enzyme cleavage sites
- Phosphorylation sites
- Binding motifs
- Transmembrane spanning sequences
- Protein secretion leader sequences
Do structural arrangement of motifs predict function
Not necessarily
Do sequence motifs that can be found in both proteins and DNA have biological significance?
Yes
Proteolytic enzyme cleavage sites
- cleave specific sequence
- motif
Phosphorylation sites
- critical to regulation of activity
- motif
Helix-loop-helix
common in transcription factors and consists of alpha helices bound by a looping stretch of amino acids
Helix-turn-helix
- DNA binding motif consisting of two a helices joined by a short stretch of amino acids
Zinc finger motif
- DNA binding motif consisting of two B strands
DNA replication
- has sequencing motifs like TATA box that are promoters and transcription factor binding sites
What can DNA sequence tell us
- eventual protein function and what gene might do
Major proteins of the enamel
- Amelogenin
- Ameloblastin
- Enamelin
- Kallikrin 4
- Mmp-20
Amelogenin
Stabilizes the amorphous Ca-P phase , control of apatite crystal morphology and organization, control of enamel thickness
- Amelogenins have the ability to self assemble into nanosperes and thereby guide HAP crystal formation/growth
