ANTIVIRALS - glycans and viruses

Carbohydrates

simple sugars, monosaccharides, that cant be converted into smaller sugars by hydrolysis .

e.g) glucose

Complex carbohydrates

Carbohydrates made up of more than one monosaccharide linked by glycosidic linkage for example sucrose and cellulose

Oligosaccharides

: 3-10 units (monosaccharide units)

Amylose - a starch

insoluble in cold water 

Consists of approximately 20% weight of starch

1→ 4 alpha linked linear structure

Amylopectin - a starch

• soluble in water 

• Consists of approx 80% weight of starch

• A branched structure consisting of 1-4 alpha linkage and 1-6 alpha linkage

SIALIC ACIDS

e.g) Muraminic acid

Neuraminic acids 

9C sugars which are components of polysaccharides in cells walls and are important constituents of glycoproteins and glycolipids.

Tamiflu

Sialidase inhibitor

glycan

the sugar portion attached to a protein or lipid

ROLE OF GLYCANS- 

• providing structural components, 

• determining blood group compatibility,

• modifying protein properties,

•  and playing key roles in cell signalling, 

• immune response, 

• and drug design.

peptidoglycans,

are essential components of cell walls, providing structural integrity.

proteoglycans are found in the extracellular matrix

are found in the extracellular matrix

Glycans can influence ______ of proteins

the solubility and stability

Glycans determine blood group compatibility

on the surface of blood cells determine blood groups. Receiving incompatible blood can cause agglutination (clumping of blood cells) which is dangerous.

Structure of a virus

• viral genome is contained and protected by a protein coat , known as a capsid. The complete structure is known as a virion.

  
  

• Capsids in enveloped virus

• nucleocapsid. (The envelope is a lipid bilayer membrane with glycoproteins)

RNA VIRUS -

replication occurs in the cytoplasm

RETROVIRUS -

synthesise viral DNA using RNA as a template

DNA-VIRUS -

viral mRNA is formed in the cell by viral DNA using the host cells polymerases

LIFE CYCLE OF VIRUSES

1. Virus enters a cell and transfers genetic material, sometimes also essential proteins

2. Viral genes lead to the production of viral proteins.

These viral proteins ensure that the genome replicates, 

packages genomes into virions, 

and affects the structure and/or function of the infected cell

3. Finally, new progeny viruses are released from the host cell.

Stages in virus life cycle

1. absorption

2. penetration and uncoating

3. replication and transcription (of DNA/RNA)

4. Virion release

during absorption

the virus binds to the outer surface of the host cell membrane, targeting a specific molecule, usually a glycoprotein with crucial cell function.

during penetration and uncoating,

different viruses have various approaches to introducing their nucleic acid (DNA or RNA) into the host cell, resulting in the release of the viral nucleic acid into the host cell

the replication and transcription of the viral DNA or RNA occurs,

the mechanism by which this happens varies from virus to virus. This leads to the synthesis and assembly of nucleocapsids.

virion release occurs

either through cell lysis or the process of budding, depending on the type of virus

4 properties of an ideal small molecule antiviral drug

1. Broad spectrum antiviral activity

2. Completely inhibits viral replication

3. Maintains efficacy against mutant viral strains

4. Reaches the target organ without interfering with normal cellular processes or the immune system of the host