Provided herein are compositions and systems for use in polymerase-dependent, nucleotide transient-binding methods. The methods are useful for deducing the sequence of a template nucleic acid molecule and single nucleotide polymorphism (SNP) analyses. The methods rely on the fact that the polymerase transient-binding time for a complementary nucleotide is longer compared to that of a non-complementary nucleotide. The labeled nucleotides transiently-binds the polymerase in a template-dependent manner, but does not incorporate. The methods are conducted under any reaction condition that permits transient binding of a complementary or non-complementary nucleotide to a polymerase, and inhibits nucleotide incorporation.