Homework Help: Hydrogen bonding with polypeptides

Posted by Lena on Thursday, March 3, 2011 at 9:04pm.

In a polypeptide at physiologic pH, hydrogen bonding may form between which of the following?

a) side chains of leucine residue and lysine residue
b) side chains of aspartyl residue and glutamyl residue
c) terminal amino acid group and terminal carboxyl group
d) amide group in peptide bond and aspartyl group

This is my thinking. H+ is positive so it would bind to something negative. Lysine is positive so a) would be wrong. Aspartate and glutamate are negative so I'm not too sure about that one. For c) terminal amino acid group has carbon which has a positive change so H wouldn't bind there. And then d) I have no idea.

Hydrogen bonding with polypeptides - DrBob222, Thursday, March 3, 2011 at 9:29pm
I agree with you on c.
Hydrogen bonding with polypeptides - Lena, Thursday, March 3, 2011 at 9:43pm
Apparently the correct answer is in fact d) howevere I don't even understand what d) is means.

Amide:

o=c-nh

Aspartyl:

CH2-COO-

I understand that it may bind to the O- on aspartyl but why would hydrogen binding occur b/t the c-nh when carbon is already bonded to the nitrogen?
Hydrogen bonding with polypeptides - DrBob222, Thursday, March 3, 2011 at 11:24pm
It's the H attached to the N that is hydrogen bonded to a negative part; in this case to the CH2COO^-
But c has NH2 on one end and COOH on the other.That's why I picked c.
Hydrogen bonding with polypeptides - Lena, Thursday, March 3, 2011 at 11:54pm
I'm going to have to ask my prof about this because in lecture she apparently tricked us because we all had chosen C as the answer.
Hydrogen bonding with polypeptides - Lena, Thursday, March 3, 2011 at 11:55pm
Thank you very much.

Answer this Question

Related Questions

Chemistry - 6. Which one of the following statements about chemical bonding is ...
Chemistry - Explain in terms of forces between structural units why H2O2 has a ...
chemistry - When will hydrogen bonding occur?Give an example of liquid other ...
Chemistry - Is it possible for the dispersion forces in a particular substance ...
biology - Is the tertiary structure of a protein the bonding together of several...
chemistry - What intermolecular force(s) must be overcome to do the following. (...
Chemistry - Describe the formation of hydrogen bonds in a hydrogen peroxide, ...
PLEASE HELP BIO - If the side chain of a glutamic acid residue has a pKa of 4.1...
h bonding - which exhibits hydrogen bonding (there can be more than 1) 1. IF7 2...
Chemistry - Which alcohol has the strongest intermolecular force of attraction? ...

For Further Reading

First Name:
School Subject:
Answer: