protein structures

[pistolpete007]

kaplan says on page 482 "Proteins are divided into two major classifications on the basis of tertiary structure. Fibrous proteins, such as collagen, are found as sheets or long strands, while globular proteins, such a myoglobin are spherical in shape

shaum's bio says on page 32 "a-helix.....pleated sheets......A third type is the triple helix structure of collagen"
so is collagen a 2ndary like shaums or tertiary like kaplan says?



also shaum goes on to say that Fibrous proteins (hair, silk, tendons) consists of long chains, frequently comprising repeating patterns of particular amino acids, a feature of primary structure that is rflected in the a-helical and B-pleated sheet configuration of the 2ndary sturcture.

So again whose right, kaplan that say fibrous protein a tertiary strucure (although it gave keratin as example of 2ndary a-helix). or is shaums right?

Finaly is hemoglobing a quanterary and conjugated protein?

---

Members don't see this ad.

 

[gkhan]

all proteins have prim/sec/tert/quad structures.

they just describe the protein in a 3-d way.

 

[Yahmasta19]

Here is the thing

Primary structure is basically only amino acids

Secondary structure can be alpha helix or beta sheet. When they speak of secondary structure they are speaking of a beta sheet and an alpha sheet just as their shape.

Tertiary structures is a combination of alpha - alpha -beta or alpha-beta-alpha they are connected in one chain.

Now, Quaternary structure such as hemoglobin is due to the fact that hemoglobin has more than one chain of tertiary structure. For instance, lets say that hemoglobin has one chain (alpha-alpha-alpha) + (alpha-beta-alpha) + (beta-alpha-alpha) = 3 chain.
Now this 3 chain make up the quaternary structure.

This is what i remember, you should get a book in Bio-chem and review the basic structures. Good luck.

 

[Mstoothlady2012]

yea all proteins have primary, secondary, tertiary, quaternary structure. Primary is sequence, secondary is alpha or/and beta sheets depending on the protein, tertiary is the 3D arrangement and quaternary is the arrangement of the different subunits in the protein. So I think keratin goes upto tertiary structure ( i dont think it has different subunits right?) so it could be describe from the point of view of secondary and tertiary. Secondary being the presence of alpha sheets and tertiary being how it looks in 3D perspective.

If it helps think about hemoglobin...primary?secondary?tertiary?quaternary? primary - sequence, secondary - alpha & beta sheets, tertiary - arrangement of these sheets, quarternary - arrangement of 4 subunits.

Hope this helps...

 

[userah]

all proteins have prim/sec/tert/quad structures.

they just describe the protein in a 3-d way.

not all proteins have quatenary structure, That structure is only for when you have multimeric proteins. Only multiple subunit proteins like hemoglobin have quatenary. (as opposed to myoglobin, which only has one chain)

 

[Mstoothlady2012]

true...

 

[gkhan]

not all proteins have quatenary structure, That structure is only for when you have multimeric proteins. Only multiple subunit proteins like hemoglobin have quatenary. (as opposed to myoglobin, which only has one chain)

what i meant was that its a way of classifying proteins and chracterizing them instead of what the main poster thought they were.

but i do stand corrected, not all proteins have quad structure.