TOPO I (Human DNA Topoisomerase I, N terminal Domain 1-197)

• Species; Human
• Expression Host: Baculovirus-insect cell
• Tag: His-tag
• Purity: 95%
• Molecular Weight: 25.3 kDa.
• Gene Accession Number: NM_003286.

Purification and Quality Control

The N-terminal domain (NTD) of human DNA topoisomerase I protein (residues 1-197) was expressed in a baculovirus system and purified using affinity and FPLC chromatography. The purified TOPO I (Human DNA Topoisomerase I, N terminal Domain 1-197) is greater than 95% homogeneous based on SDS-PAGE analysis.

Unit Definition (Activity)

1 unit equals 1 nanogram purified protein. 0.1 – 10 units (ng) have been tested for an in vitro relaxation assay in a 20 µl reaction and contain no detectable DNA relaxation activity.
Variable exist in different lots

Applications

Purified topo I NTD can be tested for in vitro transcription, pre-mRNA splicing, DNA binding and protein-protein interaction assays.

Formulation and Storage

The protein is in 20mM Tris-HCl pH7.9,100mM NaCl, 0.2mM EDTA, 1mM DTT and 20% glycerol. Stored at -70°C before use. Avoid repeated freeze thaw cycles.

Protein Sequence

SGDHLHNDSQ IEADFRLNDS HKHKDKHKDR EHRHKEHKKE KDREKSKHSN SEHKDSEKKH KEKEKTKHKD GSSEKHKDKH KDRDKEKRKE EKVRASGDAK IKKEKENGFS SPPQIKDEPE DDGYFVPPKE DIKPLKRPRD EDDADYKPKK IKTEDTKKEK KRKLEEEEDG KLKKPKNKDK DKKVPEPDNK KKKPKK

Background

Human DNA topoisomerase I is the best studied of the DNA topoisomerase family. It catalyzes the relaxation of both positive and negative supercoils without the requirement of energy. In addition to DNA replication and transcriptional activation, DNA topoisomerase I also plays a major role in pre-mRNA splicing, cell cycle and other gene regulatory pathways during cell growth and development.
The N-terminal 214 amino acids of topoisomerase I comprise a highly charged N-terminal domain (NTD) involved in protein-protein interactions with a number of cellular proteins, including SV40 T antigen, nucleolin, SR proteins (Cat#P3002), p53 (Cat#P2001) (1-6) and other transcription factors (7-11).

Image of SDS-PAGE / Western-blot