What kind of protein is keratin?
What's the difference between ribonucleotides and deoxyribonucleotides in regard to sugars and nitrogenous basis?

Question

anonymous · Answer

go to this site it will help you 
ttp://www.biologyreference.com/Mo-Nu/Nucleotides.html#b

anonymous · Answer

sorry put a H before the ULR

liliakarina · Answer

All right, thanks

blues · Answer

There are quite a few different kinds of keratin - all are fibrous structural proteins found in skin, hair, nails, horns, feathers, baleen (in whales, obviously) and other epidermal tissues. Keratin monomers aggregate in very specific ways to form intermediate filaments which are part of the cytoskeleton.

In general, keratins can be divided into two classes: alpha keratins (basically helical) and beta keratins (basically beta sheets). 

The alpha keratins are helical; three different monomers interact with each other to form a "superhelix" held together mostly by hydrophobic interactions between the individual keratin molecules. The non-interacting side chains tend to glycines which are small and pack much more tightly than bulky side chains, so you also have a lot of short range H bonds between the monomers. These trimers then dimerise and the resultant hexamers dimerise with other hexamers (and so on) to form the intermediate filaments.

The beta keratins form individual beta sheets, then those dimerize and polymerize to form filaments. Again, you see a lot glycines - the sheets pack tightly - and also a lot of disulfide bonds between cysteines of different kertain monomers. The end result, again, is a very strong, tightly packed, stable molecule.