I really appreciate your exceptional way to explain different concepts related to the subject material. I consider you an exemplar of good mentor....thanx for helping me to prepare for my BIOCHEM. exam.
I think you made a mistake describing proline structure... Proline's amino terminus has a pK of >10.5, it exists in physiological pH ionized with a hydrogen attached to it. You drew it in a way that it is only a tertiary nitrogen, this is wrong. It cannot hydrogen bond because the lone pair on nitrogen is not there to resonate with the peptide bond with this attached hydrogen, not because the hydrogen is not there. It retains its flat structure because of its cyclic nature, not because of the peptide bond. Please correct me if I am wrong.. thanks.
hi,i just have a question,how does proline not have an extra H agter it forms the peptide linkage?since N bears 2H and one will be removed to form water after the peptide linkage
Hold your right hand out in front of you with your thumb pointing up and your all your fingers pointing straight in front of you. Your palm should be facing left, and the back of your hand would be facing right. Then, while keeping your thumb pointing up, curl your fingers UP and IN towards the direction your palm was initially facing, and turn your wrist to follow the direction your fingers would continue to move. Imagine forming a helix that way; that would be a right-handed helix. I hope that makes sense.
got ya, so the helix will form in the direction of your thumb and the direction in which your fingers will fold: inwards and up, so spiraling upwards. thank you for the explanation
Hi, MsTommyknocker. That's a difficult question to answer in text, but I'll try to be as simple as possible. Imagine you're holding a helix upright in your hand, and you are looking at it from above. If you took your finger from your other hand, set it on the top end of the helix and began to use your finger to follow the helix down, you would find your finger would either rotate clockwise or counter-clockwise as you progressed along the helix. If it rotated CLOCKWISE, you'd know you were dealing with a RIGHT-handed helix. Conversely, if it rotated COUNTER-CLOCKWISE, you'd know you were dealing with a LEFT-handed helix. I hope that explanation makes sense. Cheers, and happy studying!
MsTommyknocker We read polypeptide chains N to C (from the amino terminus to the carboxy terminus). So, if we were to do what I mentioned above, you'd hold the helix so that the top has the amino terminus, and you'd follow the strand down towards the carboxy terminus (your finger would follow the strand N to C). I hope that helps.
my biochem coordinator who is also my current lecturer for the current series is SO SHIT. His attitude, his teaching skills (he literally copied the same powerpoint from online) and I really can't understand much of his lecture due to his heavy accents. Urghhhh, really pissing me off so much in every lecture -_- thank God youtube has creators like you to help us!
RGRG .RGRG Lol. This was a LONG time ago when my videos where longer and nowhere near as good as they are now (in my opinion). I think my handwriting is way better in the newer videos, as I pre-wrote things and didn't have to rush writing. :]
