EP  Engineering Proteins

 

EP1 Synopsis

The story of proteins and enzymes, the role of DNA in protein synthesis and the use of chemistry to ”engineer‘ proteins with specific structure and properties. Main topics:

• the biological importance of proteins;

• amino acids: the building blocks for proteins;

• enzymes;

• the structure of proteins;

• DNA: its structure and its role in protein synthesis;

• engineering proteins for particular needs.

 

EP2 Learning outcomes

 

Candidates should be able to:

(a)      recall that proteins are condensation polymers formed from amino acid monomers;

 

(b)     recognise and describe the generalised structure of amino acids;

 

(c)     describe the acid-base properties of amino acids and the formation of zwitterions;

 

(d) describe the formation and hydrolysis of the peptide link between amino acid residues in proteins and the use of paper chromatography to identify amino acids;

 

(e)     explain the importance of amino acid sequence in determining the properties of proteins, and account for the diversity of proteins in living things;

 

(f)   recognise stereo-isomers: cis-trans and optical isomers (enantiomers);

 

(g) explain and use the term ”chiral‘ as applied to a molecule;

 

(h) build models and draw and interpret diagrams to represent optical isomers of

     simple  molecules;

 

(i)  describe how nuclear magnetic resonance spectrscopy (n.m.r.) can be used for

             the  elucidation of molecular structure;

 

(a)     interpret nuclear magnetic resonance spectra for simple compounds given

       relevant  information (reference to splitting of the resonances is not required);

 

(k)     write an expression for the equilibrium constant, Kc, for a given

            homogeneous reaction;

 

(l)   describe the way in which changes of temperature and pressure affect the magnitude of the equilibrium constant;

 

(i)       use values of Kc, together with given data on equilibrium concentrations, to calculate the composition of equilibrium mixtures;

 

(j)       distinguish between the primary, secondary and tertiary structure of proteins;

 

(k)     explain the role of hydrogen bonds and other intermolecular forces in determining the structure and properties of proteins;

 

(p) describe the double helix structure of DNA in terms of a sugar-phosphate backbone and attached bases (recall of detailed structure is not required);

 

(q) explain the significance of hydrogen bonding in the pairing of bases in DNA, and relate to the replication of genetic information;

 

(r)   explain how DNA encodes for the amino acid sequence in a protein;

(s)     use empirical rate equations of the form: rate = k[A]m[B]n where m and n are integers;

 

(t)      explain and use the terms:  rate of reaction, rate constant, order of reaction (both overall and with respect to a given reagent);

 

 

(u)  describe experimental methods for measuring the rate of reactions;

 

(v)   use experimental data to find the order of a reaction (zero, first or second order)

 

(w)

use given data to calculate half-lives for a reaction;

 

 

(x)

show awareness of the industrial importance of enzymes;

 

 

(y)

 

describe and explain the characteristics of enzyme catalysis, including:

 

 

 

    (i)

specificity,

 

 

(ii)

temperature and pH sensitivity,

 

 

(iii)

inhibition;

 
           

 

(z)      account for the specificity of enzymes in terms of a simple ”lock and key‘ model

              of  enzyme action;

 

(aa)   explain in outline the technique of ”genetic engineering‘;


      (bb) discuss applications of genetic engineering techniques.