The key difference between NAG and NAM is that the N-acetylglucosamine (NAG) does not have a pentapeptide attached to it while the N-acetylmuramic acid (NAM) has a pentapeptide attached to it.
Peptidoglycan is unique to bacteria, and it is the component that is present in the bacterial cell wall. In the bacterial cell wall, there is a layer of peptidoglycan. Based on the thickness of this layer, bacteria differentiate into two major groups that are important in bacterial characterization. In Grams positive bacteria, there is a thick peptidoglycan layer while in Grams negative bacteria, a thin peptidoglycan layer is present. Peptidoglycan is a polymer composed of sugars and amino acids. N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) are two alternating amino sugars present in the peptidoglycan layer of the bacterial cell wall.
CONTENTS
1. Overview and Key Difference
2. What is NAG
3. What is NAM
4. Similarities Between NAG and NAM
5. Side by Side Comparison – NAG vs NAM in Tabular Form
6. Summary
What is NAG?
N-acetylglucosamine is an amino sugar present as a component of the peptodoglycan layer in bacteria. It is a derivative of glucose.
Figure 01: NAG
It locates between two NAM molecules in the oligopeptides of the peptidoglycan layer. NAG provides structure to peptidoglycan layer, hence provides strength to the bacterial cell wall. Structurally NAG is similar to NAM. However, NAG does not have a pentapeptide attached to it.
What is NAM?
NAM is the second component of the peptidoglycan monomer of bacteria. It is an ether made from lactic acid and N-acetylglucosamine. NAM has a pentapeptide attached to it. Hence it facilitates the cross-linking between oligopeptides of the peptidoglycan layer.
Figure 02: NAM
Moreover, NAM locates between two NAG molecules. Both NAM and NAG together provide the strong lattice structure to peptidoglycan layer.
What are the Similarities Between NAG and NAM?
- Both NAG and NAM are amino sugars.
- They are present in the bacterial cell wall.
- NAG and NAM are components of a peptidoglycan monomer.
- Both have a ring structure.
- Both provide strength to the bacterial cell wall.
What is the Difference Between NAG and NAM?
NAG and NAM are two amino sugars present in the peptidoglycan layer of bacteria. The NAG is an amide composed of glucosamine and acetic acid. The NAM is an ether of lactic acid and N-acetylglucosamine. NAM molecule has a peptide chain attached to it which facilitates cross-linking between oligopeptides of the peptidoglycan layer. On the other hand, NAG does not have a peptide chain attached to it. Instead, NAG locates between two NAM molecules and provides the structure to the peptidoglycan layer. This is the key difference between NAG and NAM
Summary – NAG vs NAM
NAG and NAM are two amino sugars that are components of a peptidoglycan monomer. NAM facilitates cross-linking between peptide chains of peptidoglycan layer. NAG also provides structural support to the peptidoglycan layer. Both NAM and NAM together make a strong layer that protects bacteria from the outside environment. This is the difference between NAG and NAM.
Reference:
1.Editors. “Peptidoglycan (Murein) – Definition, Structure & Function.” Biology Dictionary, Biology Dictionary, 29 Apr. 2017. Available here
2.Libretexts. “2.3: The Peptidoglycan Cell Wall.” Biology LibreTexts, Libretexts, 3 Sept. 2017. Available here
Image Courtesy:
1.’N-Acetylglucosamine’By Yikrazuul – Own work, (Public Domain) via Commons Wikimedia
2.’N-Acetylmuramic acid’By Yikrazuul – Own work, (Public Domain) via Commons Wikimedia