Patent ID: 7807356

Claim:
A composition having the structure (I): P1-Nus-P2-Lnk-Obs (I) or a salt, conjugate base, tautomer, or ionized form thereof, wherein: P1 is a phosphate group, Nus is a nucleoside moiety comprising a sugar group bound to a purine or pyrimidine base; P2 is a phosphate group; Lnk is a linking group; wherein Lnk has the structure —(CH 2 ) m -Lkg-(CH 2 ) n — wherein m and n are integers independently selected from the range of 1 to about 12, and Lkg is a linkage selected from ether-, thio-, amino-, oxo-, ester-, and amido-; and Obs is an observable label moiety.