[Quickregi]

Hi, i have a problem I need help with.

A monovalent ligand binds to a protein with six independent, identical binding sites.
What is the probability that a given protein molecule is bound by at least five ligand
molecules at equilibrium if K^μ_D = 1 nM and L₀= 2 nM (constant)?

Now I was thinking that I could use the equation V=n[L]₀/(K^μ_D+[L]₀) where n=number of binding sites/protein concentration, but I'm not sure how to find the protein concentration.  I was thinking I could use the fact that Kd=[P][L]/[C] to find the protein concentration, but I'm not sure if Kd=K^μ_D in this case. Also, once I find V, which is the ratio of the total bound ligand over the total protein binding sites (I think), I don't know how to use this to find the probability of binding to 5 or more ligand molecules at equilibrium.

 I'd really appreciate some direction, thanks.