HOME >> BIOLOGY >> NEWS
Peering at a machine that pries DNA apart

X-ray crystallography gives scientists new understanding of molecular motor

Boston, MA--October 12, 1999--Harvard researchers have created the first atomic-resolution image of a donut-shaped enzyme, or helicase, that unwinds the DNA double helix to expose its genetic letters for DNA replication. Michael Sawaya, postdoctoral fellow in the lab of Tom Ellenberger, associate professor of biological chemistry and molecular pharmacology (BCMP), worked out the X-ray crystallographic structure reported in the October 15 Cell. The structure is rendered in pictures that show how six individual polypeptide lobes arrange themselves in space to look a bit like a ring of bread buns. It affords researchers the first detailed glance at a family of proteins that remain enigmatic in spite of their recognized status as a fundamental molecular machine of the cell.

"We know next to nothing about how these helicases move on DNA," says Ellenberger. Helicases have become a competitive field of inquiry because defects in human forms underlie several diseases, including the cancer-prone Bloom's syndrome and a disease of premature aging called Werner syndrome. Helicases are interesting for several reasons. First, they are molecular motors, just like myosin, which moves along actin fibrils to contract a muscle, or kinesin, which transports cargo along microtubules. The ring-shaped kind of helicase threads one strand of DNA through its central hole and zips along the double strand at breakneck speed, ploughing through 300 paired nucleotides per second while shoving the second strand out of the way. The enzyme is powerful, too. Other researchers have placed "roadblocks" in the helicase's way by binding proteins on the DNA's back. Yet the helicase knocked these off as it forced its way through.

Second, helicases came in different shapes--some are monomers, others dimers--and they do all sorts of things. The ring-shaped, hexameric helicase studied here spearhea
'"/>

Contact: Peta Gillyatt
gillyatt@hms.harvard.edu
617-432-0443
Harvard Medical School
15-Oct-1999


Page: 1 2 3 4

Related biology news :

1. Peering inside the body, with a new spinliterally
2. Peering inside a blood vessel
3. Israeli scientists reveal the plan of a key cellular machine
4. New understanding of the machinery of flinching
5. RNA could form building blocks for nanomachines
6. Researchers look into components of RNA silencing machinery
7. How DNA repair machinery is a Two-Way Street
8. Mutant biological machine makes proteins but cant let go
9. Powerful machines are coming in small packages
10. Portable kidney dialysis machine developed
11. Purdue biologists expose the inner workings of viral machine

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/25/2019)... ... 24, 2019 , ... In a letter sent to U.S. ... of 62 individual scientists, bioethicists, and biotechnology executives, including past-presidents and current board ... across industry and academia called for collaboration on a binding global moratorium on ...
(Date:4/25/2019)... ... April 25, 2019 , ... Aniara Diagnostica, a ... strengthened its commitment to meeting today’s highest standards for product quality and cost-efficient ... of its targeted proteases is needed. Current uses concern protein isolation, removal of ...
(Date:4/18/2019)... ... April 18, 2019 , ... Medpricer, the ... launch of mSource® AI Contract Text Analysis. This contract mining tool uses machine ... contracts, truly optimizing purchased services spend at record speed. It can analyze more ...
Breaking Biology News(10 mins):
(Date:4/16/2019)... ... 16, 2019 , ... Fulcrum Biometrics , a leading ... South Pacific (BSP), the largest regionally owned bank in the South Pacific, selected ... to deliver a fingerprint-based Know Your Customer (KYC) banking solution that is being ...
(Date:4/10/2019)... ... ... After more than three months of renovation, Lajollacooks4u is set to reveal its ... modern lighting and fixtures, and will provide additional workspace for the many guests who ... the demand for our team-building events and cooking classes over the last eleven years,” ...
(Date:4/8/2019)... ... April 08, 2019 , ... CallTower, a ... the launch of their app integration solution, CT Cloud Unite. CT Cloud ... while using CT Cloud Voice and Skype for Business solutions. This robust integration ...
(Date:4/4/2019)... ... 2019 , ... LeadingBiotech, an exclusive event series bringing biopharma ... Boston CEO conference to be held May 28-29, 2019 at Boston’s Four Seasons ... panels and discussions from past, present and future change-makers. , LeadingBiotech, ...
Breaking Biology Technology:
Cached News: