Modular structure of protein Flashcards
What do simple secondary structures fold into?
Simple secondary structures fold combine to form structural motifs or larger functional domains
What are motifs and domains in terms of structure?
Independent order of structure
Where are motifs commonly found?
Commonly found and conserved across functionally related proteins
What are motifs?
Combination of two or more secondary structures to form a recognisable folded arrangement
What are motifs organised or combined into?
Organised or combined into larger structural and functional domains
What is the EF hand and what does it resemble?
Is a motif which allows the binding of Ca2+ and resembles a helix turn
What does the greek key motif consist of?
Consists of antiparallel beta strands
Why are greek key motifs common?
Form easily during protein folding process and therefore common and isn’t associated with a specific function
What happens in a beta barrel?
Beta strands wrap around to form circular tunnel
What is a domain?
Complex structure at the tertiary or quaternary level often involving interactions between distant parts of a protein or motifs
What does each chain of HB have a similar structure to and what does this suggest?
• Each chain of HB has a very similar tertiary structure to a single myoglobin chain
○ This strongly suggests evolution from a common ancestral O2 binding polypeptide
What are the 4 types of DNA binding motifs?
Helix loop helix
Leucine Zipper
Helix turn helix
Zinc finger
What provides specificity to DNA binding motifs?
Amino acid sequence of a DNA binding motif provides specificity
Where is a Helix loop helix(DNA binding motif) found?
Found in some transcription factors
What is the central portion of a helix loop helix made from?
Central portion made from overlapping helices that form a structure enabling dimerization
