Helix-coilme.de Previously discussed is ing model, a good model tar phase transitions and Many other processes
- spins s;
a- Helixis a canvas SS - element in
proteins ←
Lets say Evil -- 0
far are residue q= EBEN (essay +PE model)
= left e
G
of
pvspeeme
Consider short peptide as example eg 4 sites
Q=( It kM= It 4kt 6k't 4k Stk "
cuffs ( Nm ) number of HC strings CcccHH HH CHUN etc
HCHYI HHCH HHHC
H2O
How do we get ( fu> from partition fine
see that f" -- niff Eton )NE
if Qing .fm/etPEnn=-!?fY.lkn "
Q -I
= Hifk as before far are site
How does this correct to energy description
LEtot = -Cnn>Candles = -Ota = - oQ. OIop op
I f ke e '-BE
¥p= + EetBt -
- t E K Cf,µ so set? = -Ek diff so fit = Enugu > = - atony = I %I -
Hetero polymers : proteins are
chains of AA with
Each site could be different and at
this independent level , different Ids
So Ka , kg . . -
right now CHCH HC
B-F= ( 1)Lkklk# CHUI - - E
adding I > I makes stretches of
helices
fired prob - exact analogy Z¥ns' in Id exact partihm
function - first phgzial approx
suppose I my lazes .
likely to hone cu HHH then HCCHCH
g
= It #µTHE Chai" - Z na Ck TIM ] -
k-2 Em adz kn "
then can get tie as I doff still complicated formula !
phy i call y
E -
- I came is army were in high E limit for solution
How do we solve exactly ?
Method calledtus
Q=¥.in?..o.i-?.....IIkxiz" "" 2- tens
= awtbx axtbz
hi Ci
←
K
Every time we multiply w we get sums of terms representing Q it first pos is a helix or coil
These end up in bottom row , easiest
to see w/ example
coil
chain of 2 ' . cc CH Hc HH i t k k t z K2
w" ill: " "
" LEAK Ii ) )
5am
( O l ) ( f tf ) = (Otc of d l = to d)
( c dlf ! I -- Ctd
and get the knotty
s is bows ten adjacent H -
w -- l 'T ' il
I I =
(KT- Nfl - H -k = YL -X ( ke th t KCI - H
( let tht EHRET a-