the structure of proteins. functions of proteins fibrous proteins – structural, e.g. collagen....

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The Structure of Proteins

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Page 1: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

The Structure of Proteins

Page 2: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Functions of Proteins

• Fibrous proteins – structural, e.g. collagen. • Globular proteins – metabolic functions, e.g.

haemoglobin. • It is their structure that allows them to carry

out their functions.

Page 3: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

• Monomer units of proteins are called amino acids.

Page 4: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

C

Page 5: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

C

Page 6: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

C

Page 7: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

C

Page 8: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

O

OC

H

CARBOXYL GROUP

H

Page 9: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

O

OC

H

CARBOXYL GROUP

H

Page 10: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

O

OC

H

CARBOXYL GROUP

H

R-GROUP (Variant)

Page 11: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsAmino Acids

CNH

H

AMINO GROUP

O

OC

H

CARBOXYL GROUP

H

R-GROUP (Variant)

Page 12: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin
Page 13: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

PRIMARY STRCUTURE – Polypeptides• Polypeptides are composed of amino acids

bonded to each other, like beads on a string• The bond that holds them together is called a

peptide bond• They are formed by loss of water so is called a

condensation reaction.

Page 14: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

PRIMARY STRCUTURE – Polypeptides

Page 15: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

PRIMARY STRCUTURE – Polypeptides• -OH from carboxyl group• -H from amino group• Forms peptide bond

Page 16: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

Secondary Structure – α helix

+ve

-ve

Page 17: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

Tertiary Structure – α helix• 3D structure is formed by further bonds,

depending on the function• Disulphide bonds – strong and not easily broken

down• Ionic bonds – easily broken down by changes in

pH (carobxy/amino groups)• Hydrogen bonds – numerous be very easily

broken down

Page 18: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Functions of Proteins

• Fibrous proteins – structural, e.g. collagen. • Globular proteins – metabolic functions, e.g.

haemoglobin. • It is their structure that allows them to carry

out their functions. • i.e. the 3D structure is v.v.v important in

carrying out it’s function• Makes proteins distinctive – interacting with

other molecules

Page 19: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of Proteins

Quaternary Structure • Complex molecules containing many

polypeptide chains

Page 20: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Structure of ProteinsExample – haemoglobin:

Page 21: The Structure of Proteins. Functions of Proteins Fibrous proteins – structural, e.g. collagen. Globular proteins – metabolic functions, e.g. haemoglobin

Test for proteins