Moreno Herrero Lab

Our group started in 2009 at the National Center of Biotechnology at Madrid with the aim of understand how protein machines involved in DNA repair work at the single molecule level. To do that we use single molecule techniques such as Atomic Force Microscopy, Magnetic Tweezers and Optical tweezers. Up to date we have a functional AFM from Nanotec Electronica and a custom-made Magnetic Tweezers setup. We are also building an Optical Tweezers setup and have access to standard biochemical techniques for nucleic acids manipulation and characterization.

Here are some pictures showing the construction of the lab from Feb 2009.

Based on knowledge from the molecular biophysics lab at TUDelft, we built a Magnetic Tweezers setup to study helicases at the single molecule level. Our setup allows to control tension and torsion of single DNA molecules and to follow the dynamics of DNA processing protein machines in real time. Here is a picture of our MT setup.

We also initiated the construction of an Optical Tweezers setup. OT machines allow measuring forces up to 100 pN on DNA molecules. These machines are particularly suited machines to study molecular motors and other protein machines that may change the structure of DNA from single to double stranded or viceversa.


The Lab also has its own Atomic Force Microscope from Nanotec Electronica: a spanish AFM company that builds and sells AFM worldwide. Our AFM is placed inside an acoustic enclosure and over a pneumatic vibration isolation table to minimize vibrations from the building.

This is one of the many projects started with the group of Dr. Mark Dillingham from University of Bristol in the context of our Starting Grant ERC Project.

Recombinational repair of DNA breaks requires processing of a DNA end to a 3-ssDNA overhang. In B.subtilis, this task is done by the helicase-nuclease AddAB which generates ssDNA overhangs terminated in a recombination hotspot CHI sequence. This is a substrate for the formation of a RecA nucleoprotein filament that searches for a homologous donor molecule and catalyses DNA strand exchange to promote repair. In this study, we have used AFM to visualize and characterize the products of reactions including AddAB and double-stranded DNA molecules.

Researchers

University of Bristol: Mark Dillingham, Joseph Yeeles

We are very interested in developing new technologies to increase the speed of imaging of AFMs operated in liquid environment. To do that, we initiated a collaboration with Dr. Julio Gomez Lab and Nanotec. Our approach involves modification of the AFM head to use small cantilevers; to use faster scanners; and to program faster adquisition boards. We aim to reach a realistic imaging rate of 1 frame per second on DNA in buffer.

Researchers

UAM: Julio Gomez, David Martinez
Nanotec: Rafael Fernandez, Pablo Ares

GC-rich DNA shows in circular-dicroism experiments a signal compatible with A-form DNA. We investigated the mechanical properties and stability conditions of GC-rich DNA and compared these with a control DNA of equal GC/AT content under a variety of buffers and a wide range of forces. To do this study we used Magnetic Tweezers and AFM.

Researchers

CNB: Borja Ibarra, Silvia Hormeno
IMDEA nanociencia: Ricardo Arias