Numbers

1°

The abbreviation for primary. 1° sequence refers to the letters of DNA, RNA, or protein. 1° transcript refers to an unprocessed RNA that still contains its introns.

2°

The abbreviation for secondary. Most frequently used for generalizing protein and RNA structures; for example, the a-helix and hair-pin are common 2° structures.

3´

The end of a nucleic acid sequence; often used with UTR.

5´

The start of a nucleic acid (DNA or RNA) sequence; often used in conjunction with UTR (e.g., 5´UTR). Nucleotide sequences are conventionally written with the 5´ end at the left. DNA molecules are usually double-stranded but when written, usually only the 5´ to 3´ strand is displayed. The complementary strand has reversed polarity (3´ to 5´).