Struktura a funkce peptidů a proteinů

H2N COOH

CH2

R H2N COOH

CH2R

L-(S)-

*

*

Configuration of amino acids

H2N COOH

CH2

HS

L-(R)-

*

Primary Structure – amino acids sequence (encoded in genes)

Bovine insuline

Secondary Structure – conformation of the polypeptide chain

Peptide bond is planar

Conformation of the peptide bond

almost always trans

Conformation of the peptide bond

in Pro trans and cis in balance

Free rotation about C-N and C-C bonds

Ramachandran diagram

Alpha helix

Structure of ferritine – a largely alpha helical protein

Beta (Pleated) Sheet

Distance between two adjacent amino acid = 3.5 Å

(in aplha helix 1.5 Å)

Beta Sheets are stabilized by H-bonds between strands

Antiparallel Beta Sheets

Points to C-end

Parallel Beta Sheets

Mixed Beta Sheets

Twisted Beta Sheets

Fatty acid-binding protein – a protein rich in beta sheets

Reverse (beta) Turn

Tertiary Structure – 3D structure (folding)

3D structure of myoglobin

Structure of myoglobin – hydrophobic amino acids in

yellow, charged (hydrophilic) in blue