How to calculate linking number?

TLS Online TPP Program

#Id: 10008

#Unit 4. Cell Communication and Cell Signaling

The freed C-terminal is not involved in signaling and is often degraded, whereas the N-terminal becomes the active Hedgehog protein intended for secretion

TLS Online TPP Program

#Id: 10009

#Unit 4. Cell Communication and Cell Signaling

Secretion requires the addition of cholesterol and palmitic acid to the Hedgehog protein

TLS Online TPP Program

#Id: 10010

#Unit 4. Cell Communication and Cell Signaling

Two membrane proteins, 

Smoothened (Smo) 

Patched (Ptc)

TLS Online TPP Program

#Id: 10011

#Unit 4. Cell Communication and Cell Signaling

Smo has seven TM α helices, is a member of the GPCR superfamily, and is related in sequence to the Fz.

TLS Online TPP Program

#Id: 10012

#Unit 4. Cell Communication and Cell Signaling

Ptc contains 12 TM α helices and structurally similar

to the Niemann-Pick C1 protein, a cholesterol transporting member of the ABC superfamily

TLS Online TPP Program

#Id: 10013

#Unit 4. Cell Communication and Cell Signaling

In the absence of Hh,

Ptc inhibits Smoothened and then degraded in proteasomes