Parkin protein !

New research reveals that Parkin, a protein linked to some cases of early-onset Parkinson's disease, regulates how cells in our bodies take up and process dietary fats. The finding suggests that defective Parkin may contribute to early-onset Parkinson's by changing the amount and types of fat in the body.Parkinson's disease, a complex, progressive and currently incurable neurological disorder, is characterized by shaking, stiffness, slowed movement and impaired balance.  Mutations in the gene for Parkin are present in as many as 37% of early-onset Parkinson's cases. The protein appears to play a role in marking proteins for recycling within the cell. However, its complex structure and other lines of evidence hint at other functions. Some studies have tied lower levels of cholesterol and fatty acids with an increased risk of Parkinson's disease. 

As to how fat may be important in Parkinson's, Researchers notes that the brain cells destroyed during the course of the disease are found in a brain region called the substantia nigra, which controls movement, among other roles. “The neurons in this part of the brain are extremely active. Each one has over 300,000 connections and is continuously transmitting information,.“These neurons require good support in the form of their fat and cholesterol membrane. If the right types of fat aren’t available, then cell integrity will be sub-par and they could be prone to damage.”

What is green fluorescent protein (GFP) ?

Green fluorescent protein is a protein found in a luminescent jellyfish (Aquorea victoria) that lives in the cold waters of the northern Pacific. Bioluminescence is the production of light by living organisms. These jellyfish contain two proteins: a bioluminescent protein called aequorin that emits blue light, and an accessory green fluorescent protein (GFP). However, what we actually see when the jellyfish fluoresces is the conversion of the blue light emitted by aequorin to a green Iight-a metabolic reaction facilitated by the GFP. Since GFP is simply a protein, it is often used both as a marker for gene transfer and for localization of proteins. There are a variety of green fluorescent proteins that can glow different colors.

Amino acid sequence directs protein folding?

Question

Insulin possesses two polypeptide chains denoted A and B that are linked by disulfide bonds. Upon denaturation by reduction of the SH groups of insulin, followed by reoxidation, only 7% of the hormone activity is recovered. This is the level of activity expected for random pairing of cysteine residues to form disulfide bonds. How can these data be reconciled with the hypothesis that the amino acid sequence directs protein folding?


Answer
Insulin is synthesized as preproinsulin that is proteolytically processed in the β cells of the islets of Langerhans in the pancreas, to give proinsulin. After synthesis and folding, a section of the molecule (the C peptide) is excised, leaving the A and B peptides connected via disulfide bonds. Thus, native insulin, lacking the C peptide, lacks some of the information necessary to direct the folding process.