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 Proteins 1
 Lec 4.2
 Lect 4.3
 Lec 4.4
 Lab 4.4

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 Lec 4.2

PROTEIN FAMILIES

 

Primary Structure (amino acid sequence)

    Motifs (sequence)

Secondary Structure (alpha helix and beta sheet)

    Motifs (structural)

    Domains

Tertiary Structure  (overall 3-D structure)

 

MOTIFS

Motifs are conserved primary sequences or simple combinations of a few secondary structural elements.

Motifs (sequence)

    Glycosylation sites, phosphorylation sites, ATP binding site

 

Motifs (structural)

 

DOMAINS

Domains are fundamental units of tertiary structure.

    These are polypeptide chains that can fold independently into a stable tertiary structure.

    They can also form units of function.

    Domains are built from structural motifs.

 

Transcription Factors (TF) - bind to DNA and turn genes on or off.

 

Helix-turn-helix motif

    DNA binding domains (H-T-H)

    Dimerization domains (alpha helix)

 

 

PROTEIN FAMILY

By swapping domains a proteins activity can be changed

New proteins are made by exchange of domains and by mutations within domains

Add additional domains or make mutations to change members of the same family.

 

Glucocorticoid receptors - similar structure with different DNA binding and hormone binding domains

 

BOXSHADErec

 

Motif Search

Look at DNA binding motif in steroid receptors

 

 

Serine Proteases

 

BOXSHADEsp

BOXSHADE_2

 

Motif Search

Compare Urokinase, Factor IX and Plasminogen

 

 

 

 

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