Steve Meeting January 29, 2003

• Took 1 M Betaine data– Michelle’s data included in these results

60 pN / s BsoBI Betaine data

• There is a definite difference between 1M betaine and previous data.

• Note: I shifted the histograms to make the 1M look less “weird”

0 10 20 30 40 50 60

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14 0 M Betaine Paper 2 fit 1 M Betaine fit

Force (pN)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

1 M Betaine

N=45

N=141

Preliminary DFS

• Probably would be good to take more data at different rates.

2 3 4 5 6 720

30

40

50

60

1 M Betaine(Sketchy)

0.333 M Betaine

1 M Betaine

Figure 4 Koch SJ and Wang MD

Mos

t pro

babl

e un

bind

ing

forc

e, F

* (

pN)

ln (loading rate (pN / s) )

Equilibrium Constant for BsoBI as a function of betaine concentration

• I don’t understand the theory enough to interpret the data.

– Can be related to # hydrating water molecules released upon binding.

– Requires knowing “osmotic pressure” as opposed to molar concentration.

• At the very least, it looks like betaine is a great way to increase the EQ constant. 0 200 400 600 800 1000

1.00E+010

2.00E+010

3.00E+010

4.00E+010

5.00E+010

Equ

ilibr

ium

Co

nsta

nt M

-1

Betaine Concentration (mM)

Ka Linear Fit of EQNORMAL_KA