logo.gif (3296 bytes)Introduction to Protein Structure

Polar Amino Acids


The side chains (R groups) of the amino acids can be divided into two major classes, those with polar side chains (shown here) and those with nonpolar side chains.

The polar amino acids include: arginine, asparagine, aspartic acid (or aspartate), glutamine, glutamic acid (or glutamate), histidine, lysine, serine, and threonine.

Polar side chains contain groups that are either charged at physiological pH or groups that are able to participate in hydrogen bonding. Exam each of the amino acids shown below and determine why it is considered polar.

Name 3 letter code 1 letter code 2-D Structure 3-D Structure
 

Arginine

 

Arg

 

R

wpe1.jpg (4014 bytes)

Ca:  

Model:  

 

Asparagine

 

Asn

 

N

wpe2.jpg (2701 bytes)

Ca:  

Model:  

 

Aspartate

 

Asp

 

D

wpe3.jpg (2599 bytes)

Ca:  

Model:  

 

Glutamine

 

Gln

 

Q

wpe4.jpg (3097 bytes)

Ca:  

Model:  

 

Glutamate

 

Glu

 

E

wpe5.jpg (2954 bytes)

Ca:  

Model:  

 

Histidine

 

His

 

H

wpe6.jpg (3144 bytes)

Ca:  

Model:  

 

Lysine

 

Lys

 

K

wpe7.jpg (3554 bytes)

Ca:  

Model:  

 

Serine

 

Ser

 

S

wpe8.jpg (2423 bytes)

Ca:  

Model:  

 

Threonine

 

Thr

 

T

wpe9.jpg (2593 bytes)

Ca:  

Model:  


Copyright 1998, 1999, 2007 by Frank R. Gorga;   Page maintained by F.R. Gorga;   Last updated: 12-Mar-2007