TY  - JOUR
A1  - Szambowska, Anna
A1  - Tessmer, Ingrid
A1  - Kursula, Petri
A1  - Usskilat, Christian
A1  - Prus, Potr
A1  - Pospiech, Helmut
A1  - Grosse, Frank
T1  - DNA binding properties of human Cdc45 suggest a function as molecular wedge for DNA unwinding
JF  - Nucleic Acids Research
N2  - The cell division cycle protein 45 (Cdc45) represents an essential replication factor that, together with the Mcm2-7 complex and the four subunits of GINS, forms the replicative DNA helicase in eukaryotes. Recombinant human Cdc45 (hCdc45) was structurally characterized and its DNA-binding properties were determined. Synchrotron radiation circular dichroism spectroscopy, dynamic light scattering, small-angle X-ray scattering and atomic force microscopy revealed that hCdc45 exists as an alpha-helical monomer and possesses a structure similar to its bacterial homolog RecJ. hCdc45 bound long (113-mer or 80-mer) single-stranded DNA fragments with a higher affinity than shorter ones (34-mer). hCdc45 displayed a preference for 3' protruding strands and bound tightly to single-strand/double-strand DNA junctions, such as those presented by Y-shaped DNA, bubbles and displacement loops, all of which appear transiently during the initiation of DNA replication. Collectively, our findings suggest that hCdc45 not only binds to but also slides on DNA with a 3'-5' polarity and, thereby acts as a molecular 'wedge' to initiate DNA strand displacement.
KW  - protein secondary structure
KW  - circular dichroism spectra
KW  - small-angle scattering
KW  - single-stranded-DNA
KW  - cyclin-dependent kinases
KW  - ray solution scattering
KW  - saccharmyces cerevisiae
KW  - escherichia coli
KW  - recj exonuclease
KW  - s-phase
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117538
SN  - 1362-4962
VL  - 42
IS  - 4
ER  -