Protein Structure

Primary Structure – The order of amino acids. Secondary Structure – The coiling or folding

of the primary structure. This is facilitated by the carbonyl groups forming hydrogen bonds with the N-H groups.

Tertiary Structure – The folding of the coil or sheet. The form of the folding is determined by the side chains on the amino acids. Thus the order, or primary structure comes into effect here.

Quaternary Structure – Not always present, this is a complex formed by multiple tertiary forms. This is often formed around metal ions.

Summary of Structures

Secondary Structure – Alpha helix

Secondary Structure – Alpha Helix

Secondary Structure - Sheet Sheets are formed by primary chains

attached by the same H-bonds as in the helix

Tertiary Structure

Various interactions contribute to the formation of the structure of a protein. Di-sulfide bonds Salt-ion interactions, called salt bridges Hydrogen Bonding Hydrophobic groups interacting.

Tertiary Structure

Quaternary Structure

Antibodies

Denaturing

To “denature” a protein is to break up it’s structure. Largely, it is the tertiary structure that is disrupted, however, any disruption of secondary, tertiary or quaternary structure applies.

Denaturing may be accomplished by: Heat Acid or base Heavy Metals Agitation Organic compounds that interact with side

chains

Enzymes

Working proteins are functional in a myriad of ways. Some proteins act as structural elements such as that in hair or collagen. Others function as enzymes. These depend very heavily on shape as the operate via a lock and key mechanism.

This mechanism can be disrupted by similar molecules that fit within the proteins. These are called inhibitors.

Computer Animation of ATP Hydrolysis

Enzymes and Inhibition

Advanced Glycosidic Products, (AGE’s)

Advanced Glycosidic End Products, (AGE’s), also known as Maillard Reaction Products are known to effect all tissue proteins and DNA.

Originally recognized in diabetics, then in normal individuals, AGE’s play a major role in diabetic complications including blindness, arteriosclerosis, joint stiffness, kidney disease and are correlated with chronic high blood sugar, a precursor to adult onset diabetes.

AGE’s are a principle components in what are thought to be normal aging processes. Characteristics associated with aging, both internal and external, are affected by blood sugar levels.**Krajcovivova-Kudlackova M. Physiol. Res. 51 313 (2002) and Baynes J.W. et. al. “The Mailard Reaction in Aging, Diabetes and Nutrition” publ. Alan R. Liss, N.Y.

Formation of cross-linked proteins

Cerami A. et. al. “Glucose and Aging” Sci. Amer. 256 90 (1986)