Protein Stucture and Function

Proteins are extemely important molecules in living organisms which have a wide range of important functions. Your forum task is too investigate the structure and function of one protein.

1) Re-read the textbook section on proteins for back ground information

2) Watch the video below for further examples of possible structures

3) Research on the internet and find one example of a protein which is important in living organisms. You must attach a picture and also write a summary of at least 150 words about the structure and function of the protein.

IMPORTANT: You must not choose any protein from the textbook. You must not choose any protein already selected by a classmate and included in the forum.


DUE DATE: You must post your forum by the start of your second class during Week 29 (11/10/10)

Insulin is a protein, which is produced in the pancreas, it is also a peptide hormone composed of 51 amino acids. It has several functions such as, it is central for regulating fat and steroids metabolism in the body, and also stops the use of fat as an energy source. When insulin is absent, glucose is not taken up by body cells and the body begins to use fat as an energy source. As its level is a central metabolic control mechanism, it is also used as a control signal to other body systems. In addition, it has several other anabolic effects throughout the body.
Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle.

Keratin is a protein that is part of the fibrous strucutal proteins. It is mainly found in the skin, hair and nails and is a important strucuture of them. Keratin can be soft or hard depending on the levels of amino acids. It contain cysteine disulfide which can create disulfide brideges.This bridges create a very strong HELIX shape, made from bonds of sulfur atoms. Keratin is made from keratinocytes, which are living cells. This protein keeps the skin waterproof and haves the ability to withstand mechanical stress. It also useful because it strengthens hair, coats and repairs damaged hair, maintains healthy skin, skin pigmentation and protection, toughens nails and bony structuret.

Buffer proteins help maintain balance in the human body. Blood
proteins have a charge which helps maintain the pH of plasma, in this
way it is a very important protein because the blood transports lots
of vital substances all over the body so without the right pH we could
not function properly. From reading this essay you can see the
importance of proteins in the world around us and how we would be lost
without them, for example we would not have any hair, nails or
skin.
miss no puedo adjuntar la foto..se la voy a mandar por mail.

Actin is a globular, protein found in all eukaryotic cells.. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans. Actin is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells.
Thus, actin participates in many important cellular processes including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape
miss no pude subir la foto, por lo cual le mando el link: http://en.wikipedia.org/wiki/File:Actin_with_ADP_highlighted.png

Casein is a phosphoprotein with aprox 20% of proteins in cow milk and cheese. Casein protein has an excellent amino acid profile and is primarily known as an extremely slow-digesting protein. It is very difficult to imagine exactly what the casein micelle looks like, infact there is mouting evidence that well-defined casein does exist, rather than the more spreadly model seen as a bowl of spaghetti.Its biological function is to carry large amounts of highly insoluble CaP to mammalian young in liquid form and to form a clot in the stomach for more efficient nutrition.Besides casein protein, calcium and phosphate, the micelle also contains citrate, minor ions, lipase and plasmin enzymes, and entrapped milk serum. These micelles are rather porous structures, occupying about 4 ml/g and 6-12% of the total volume fraction of milk. Finally, casein is divided into many groups like: alpha(s1)-casein, alpha(s2)-casein, B-casein and Kappa-casein.

casein is a protein this protein is slower absorbing from the stomach, so the blood amino acid levels don't rise quite as rapidly. The advantage of absorbing slower is that helps have more amino acids for a longer period. Casein is extracted from the milk. Casein is a very rich protein source that will feed the body at a steady rate, which makes it ideal as a dietary supplement during the day or as a night-time protein to feed the body while you sleep. Casein is the best protein to take before to sleep and maybe the only one you should take because when the body needs a steady supply of proteins while the muscles repair and rebuild during the night your body needs to keep going for six to eight hours during your sleep without food.

Fibrin is a fibrous protein involved in the clotting of blood, and is non-globular.
It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site. Excessive generation of fibrin due to activation of the coagulation cascade leads to thrombosis (clot). premature Lysis of fibrin leads to haemorrhage.
Disease of the liver can lead to a decrease in fibrinogen(soluble plasma glycoprotein, synthesised by the liver, that is converted by thrombin into fibrin during blood coagulation) production or the production of abnormal fibrinogen molecules with reduced activity (dysfibrinogenaemia). hemophiliacs: have reduced, absent, dysfunctional fibrin. The structure is mainly made up of single alpha helices .

A kinesin is a protein belonging to a class of motor proteins found in eukaryotic cells.
Kinesins move along microtubule cables powered by the hydrolysis of ATP (thus kinesins are ATPases).
The active movement of kinesins supports several cellular functions including mitosis, meiosis and transport of cargo such as axonal transport. Most kinesins walk towards the plus end of a microtubule which, in most cells, entails transporting cargo from the centre of the cell towards the periphery. This form of transport is known as anterograde transport.

Picture: the kinesin motor domain

Crystallographic structure of the human kinesin motor domain depicted as a rainbow colored cartoon (N-terminus = blue, C-terminus = red) complexed with ADP (stick diagram, carbon = white, oxygen = red, nitrogen = blue, phosphorus = orange) and a magnesium ion (grey sphere)[img]
https://i.servimg.com/u/f27/15/77/99/18/kinesi11.jpg