Disulfide bridges???

[rav4182]

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I'm really confused, i keep getting different answers to this question. Some sources say disulfide bridges are a part of primary strucuture and others say its tertiary structure.

WHICH IS IT???

wikipedia and numerous other online sources say its primary

cliffs ap bio and datqvault say its tertiary

 

[casper22]

I'm really confused, i keep getting different answers to this question. Some sources say disulfide bridges are a part of primary strucuture and others say its tertiary structure.

WHICH IS IT???

wikipedia and numerous other online sources say its primary

cliffs ap bio and datqvault say its tertiary

Even Barrons AP says tertiary...I would go with tertiary...the reasoning being..

Primary is the unique linear sequence of amino acid...basically the three letter definations..

Tertiary is the three dimensional shape of the protein...and hence there are multiple cysteine amino acids where the bridge can be formed..

This may not seem too technical but that is how I remember it...🙂

 

[fellforit]

Yeah, there's no way it's primary. Not sure why your sources are saying that, but... They're wrong.

Go tertiary. 👍

 

[dentalWorks]

I'm really confused, i keep getting different answers to this question. Some sources say disulfide bridges are a part of primary strucuture and others say its tertiary structure.

WHICH IS IT???

wikipedia and numerous other online sources say its primary

cliffs ap bio and datqvault say its tertiary

Primary structure = just amino acids glued head-to-ass (COVALENT)
2ndary structure = mostly Hydrongen bonding (weak-interactive force)
tertiary structure = some more weak interactive forces (like side chains of amino acids and more Hydrogen bonds) but also some COVALENT foces (like disulfide bonds)
quaternary structure = same forces as tertiary.

 

[Juggernauts]

glued head-to-ass (COVALENT).

On the tertiary structure of proteins you have the following
-Hydrophobic Interactions
-van der Waals forces
-Ionic Bonding (between a backbone amino group and a much further down the chain backbone carboxyl group)
-Covalent Bonding (The disulfide bridge of two cysteine amino acids)
-Hydrogen Bonding between "R groups" of the amino acids. This is different than the hydrogen bonding on the "backbone" which is what provides the alpha helix and beta sheet at the secondary structure level. It's a trivial difference, but a difference none the less.

 

[dantemac]

Primary = Amino Acid sequence only
Secondary = H-Bonding resulting in alpha helices or beta-pleated sheets
*Tertiary = Bonds between R-groups (including cysteine, which has the sulfide group)
Quaternary = Bonds between multiple polypeptide chains.