Modified nucleotides and methods of preparing and using same

A compound having the structure:

• ##STR26## wherein B represents a 7-deazapurine or a pyrimidine moiety covalently bonded to the C.sup.1' -position of the sugar moiety, provided that when B is a 7-deazapurine, it is attached at the N.sup.9 -position of the deazapurine, and when B is a pyrimidine, it is attached at the N.sup.1 -position of the pyrimidine;
• wherein A represents a moiety selected from the group consisting of biotin and iminobiotin;
• provided that if B is a 7-deazapurine, A is attached to the 7-position of the deazapurine, and if B is a pyrimidine, A is attached to the 5-position of the pyrimidine, A being attached to B directly or through a linkage group, said linkage group not interfering substantially with the characteristic ability of A to form a detectable complex with one of avidin, streptavidin or antibodies to biotin or iminobiotin;
• wherein X represents a moiety selected from the group consisting of:
• ##STR27## wherein Y is --OH and Z is --OH or --H.

A poly- or oligonucleotide sequence which comprises at least one of a moiety having the structure:

• ##STR29## wherein B represents a purine, a 7-deazapurine or a pyrimidine moiety covalently bonded to the C.sup.1' -position of the sugar moiety, provided that when B is a purine or a 7-deazapurine, it is attached at the N.sup.9 -position of the purine or deazapurine, and when B is a pyrimidine, it is attached at the N.sup.1 -position of the pyrimidine;
• wherein A represents a moiety selected from the group consisting of biotin and iminobiotin;
• provided that if B is a purine, A is attached to the 8-position of the purine, if B is a 7-deazapurine, A is attached to the 7-position of the deazapurine, and if B is a pyrimidine, A is attached to the 5-position of the pyrimidine, A being attached to B directly or through a linkage group, said linkage group not interfering substantially with the characteristic ability of A to form a detectable complex with one of avidin, streptavidin or antibodies to biotin or iminobiotin;
• and wherein Z represents:
• ##STR30##

A double-stranded RNA or DNA duplex or DNA-RNA hybrid which comprises:

• (i) in one strand a poly- or oligonucleotide sequence which comprises at least one of a moiety having the structure:
• ##STR32## wherein B represents a purine, a 7-deazapurine or a pyrimidine moiety covalently bonded to the C.sup.1 -position of the sugar moiety provided that when B is a purine or a 7-deazapurine, it is attached at the N.sup.9 -position of the purine or deaazapurine, and when b is a pyrimidine, it is attached at the N.sup.1 -position of the pyrimidine;
• wherein A represents a moiety selected from the group consisting of biotin and iminobiotin;
• provided that if B is a purine, A is attached to the 8-position of the purine, if B is a 7-deazapurine, A is attached to the 7-position of the deazapurine, and if B is a pyrimidine, A is attached to the 5-position of the pyrimidine, A being attached to B directly or through a linkage group, said linkage group not interfering substantially with the characteristic ability of A to form a detectable complex with one of avidin, streptavidin or antibodies to biotin or iminobiotin;
• and
• wherein Z represents ##STR33## and (ii) in the second strand, a poly- or oligonucleotide sequence containing neither a biotin nor iminobiotin.