Method Using A Nonlinear Optical Technique for Detection of Interactions Involving A Conformational Change

Abstract

A nonlinear optical technique, such as second or third harmonic or sum or difference frequency generation, is used to detect binding interactions, or the degree or extent of binding, that comprise conformational change. In one aspect of the present invention, the nonlinear optical technique detects a conformational change in a probe due to target binding. In another aspect of the invention, the nonlinear optical technique screens candidate probes by detecting a conformational change due to a probe-target interaction. In another aspect of the invention, the nonlinear optical technique screens candidate modulators of a probe-target interaction by detecting a conformational change in the presence of the modulator.

1 - 5 . (canceled) 
     
     
         6 . A method for screening one or more candidate modulator molecules for the ability to modulate an interaction between a test molecule and its binding partner comprising: (a) illuminating a sample with one or more light beams at one or more fundamental frequencies, said sample comprising said test molecule exposed to (i) said binding partner, and (ii) said one or more candidate modulator molecules; and (b) measuring one or more physical properties of a nonlinear optical light beam emanating from said sample; wherein a change in the value of said one or more physical properties measured in step (b) relative to the value for said one or more physical properties measured in the absence of exposure to said one or more candidate modulator molecules indicates that said one or more candidate modulator molecules modulate the interaction between said test molecule and its binding partner. 
     
     
         7 . The method of  claim 6 , wherein said test molecule is bound to one or more nonlinear-active labels. 
     
     
         8 . The method of  claim 6 , wherein said test molecule is nonlinear-active in the absence of an exogenous nonlinear-active label bound to the test molecule. 
     
     
         9 . The method of  claim 6 , wherein said candidate binding partners are bound to one or more nonlinear-active labels. 
     
     
         10 . The method of  claim 6 , which further comprises comparing the value of said physical properties measured in step (b) with the value of the physical properties measured in the absence of exposure to said one or more candidate binding partners. 
     
     
         11 - 20 . (canceled) 
     
     
         21 . The method of  claim 10 , wherein the value measured in the absence of said one or more candidate binding partners is measured in the presence of a control, wherein said test molecule does not undergo a conformational change upon binding said control. 
     
     
         22 . A method for screening one or more candidate modulator molecules for the ability to modulate an interaction between a test molecule and its binding partner comprising:
 (a) illuminating a sample with one or more light beams at one or more fundamental frequencies, said sample comprising said test molecule exposed to (i) said binding partner, and (ii) said one or more candidate modulator molecules; and (b) measuring one or more physical properties of a nonlinear optical light beam emanating from said sample; wherein a change in the value of said one or more physical properties measured in step (b) relative to the value for said one or more physical properties measured in the absence of exposure to said one or more candidate modulator molecules is used in a drug screen and indicates that said one or more candidate modulator molecules modulate the interaction between said test molecule and its binding partner.   
     
     
         23 . The method of  claim 22 , wherein said test molecule is bound to one or more nonlinear-active labels. 
     
     
         24 . The method of  claim 22 , wherein said test molecule is nonlinear-active in the absence of an exogenous nonlinear-active label bound to the test molecule. 
     
     
         25 . The method of  claim 22 , wherein said candidate binding partners are bound to one or more nonlinear-active labels. 
     
     
         26 . The method of  claim 22 , which further comprises comparing the value of said physical properties measured in step (b) with the value of the physical properties measured in the absence of exposure to said one or more candidate binding partners. 
     
     
         27 . The method of  claim 26 , wherein the value measured in the absence of said one or more candidate binding partners is measured in the presence of a control, wherein said test molecule does not undergo a conformational change upon binding said control. 
     
     
         28 . A method for screening one or more candidate modulator molecules for the ability to modulate an interaction between a test molecule and its binding partner comprising:
 (a) illuminating a sample with one or more light beams at one or more fundamental frequencies, said sample comprising said test molecule exposed to (i) said binding partner, and (ii) said one or more candidate modulator molecules; and (b) measuring one or more physical properties of a nonlinear optical light beam emanating from said sample; wherein a change in the value of said one or more physical properties measured in step (b) relative to the value for said one or more physical properties measured in the absence of exposure to said one or more candidate modulator molecules indicates an occurrence of a binding event due to a conformational change.   
     
     
         29 . The method of  claim 28 , wherein said test molecule is bound to one or more nonlinear-active labels. 
     
     
         30 . The method of  claim 28 , wherein said test molecule is nonlinear-active in the absence of an exogenous nonlinear-active label bound to the test molecule. 
     
     
         31 . The method of  claim 28 , wherein said candidate binding partners are bound to one or more nonlinear-active labels. 
     
     
         32 . The method of  claim 28 , which further comprises comparing the value of said physical properties measured in step (b) with the value of the physical properties measured in the absence of exposure to said one or more candidate binding partners. 
     
     
         33 . The method of  claim 32 , wherein the value measured in the absence of said one or more candidate binding partners is measured in the presence of a control, wherein said test molecule does not undergo the conformational change upon binding said control.