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Institute of Physiology and Pathophysiology

Single Molecules

Figure 1: Schematic experimental set-up: actin filaments move over a surface of myosin or heavy meromyosin
Figure 2: Movement of fluorescently labeled actin filaments recorded with a highly sensitive CCD camera

Molecular dynamics in the in vitro motility assay

The ability of heart and skeletal muscle to contract is based on the fundamental interaction of the two contractile proteins actin and myosin. This basic interaction can be studied in the in vitro motility assay originally devised by Kron and Spudich (1986), where fluorescently labeled actin filaments move over a surface of immobilised myosin or heavy meromyosin. The motion of actin filaments is recorded with a highly sensitive fluorescence imaging set-up.


Many parameters of this motion have been shown to be of significant importance for our understanding of the acto-myosin interaction, as e.g. the filament velocity is thought to be directly correlated to the unloaded shortening velocity of muscle fibers and therefore a direct reflection of the cross-bridge turnover rate. Also this assay is ideally suited to screen the functional domains of myosin, such as the nucleotide binding site, the actin binding site, the converter region and the lever arm. Furthermore myosin isoforms and actin mutants can be selectively studied in this assay.


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Force measurements with optical tweezers

Optical tweezers is the name of a technique for holding small objects such as polystyrene beads in the focus of a laser beam. The diffraction of the laser at the bead surface produces a force that always directs the bead towards the laser focus. This effect is simply due to the geometry of the configuration and can be applied to measure very small forces, like the force between a single myosin and actin molecule.

Recent Publications


Modulation of glutathione peroxidase activity by age-dependent carbonylation in glomeruli of diabetic mice. J Diabetes Complications. 2018 Feb;32(2):130-138. doi: 10.1016/j.jdiacomp.2017.11.007. Epub 2017 Nov 22.


Sensitive mass spectrometric assay for determination of 15-deoxy-Δ12,14-prostaglandin J2 and its application in human plasma samples of patients with diabetes. Anal Bioanal Chem. 2018 Jan;410(2):521-528. doi: 10.1007/s00216-017-0748-1. Epub 2017 Nov 16.


Magnolol inhibits venous remodeling in mice. Sci Rep. 2017 Dec 19;7(1):17820. doi: 10.1038/s41598-017-17910-0.


Hypertension-evoked RhoA activity in vascular smooth muscle cells requires RGS5. FASEB J. 2017 Dec 5. pii: fj.201700384RR. doi: 10.1096/fj.201700384RR. [Epub ahead of print]


Role of protein carbonylation in diabetes. J Inherit Metab Dis. 2017 Nov 6. doi: 10.1007/s10545-017-0104-9. [Epub ahead of print]


AP-1 Oligodeoxynucleotides Reduce Aortic Elastolysis in a Murine Model of Marfan Syndrome. Mol Ther Nucleic Acids. 2017 Dec 15;9:69-79. doi: 10.1016/j.omtn.2017.08.014. Epub 2017 Sep 20.


Allosteric inhibition of carnosinase (CN1) by inducing a conformational shift. J Enzyme Inhib Med Chem. 2017 Dec;32(1):1102-1110. doi: 10.1080/14756366.2017.1355793.


Transcription factor decoy technology: a therapeutic update. Biochem Pharmacol. 2017 Nov 15;144:29-34. doi: 10.1016/j.bcp.2017.06.122. Epub 2017 Jun 19. Review.


Local oxygen homeostasis during various neuronal network activity states in the mouse hippocampus. J Cereb Blood Flow Metab. 2017 Nov 3; 271678X17740091. doi: 10.1177/0271678X17740091


Subtype-specific differentiation of cardiac pacemaker cell clusters from human induced pluripotent stem cells. Stem Cell Res Ther. 2017 Oct 16;8(1):229. doi: 10.1186/s13287-017-0681-4.

Institute of
Physiology and Pathophysiology

Heidelberg University

Im Neuenheimer Feld 326

69120 Heidelberg


Phone:+49 6221 54-4035
Fax:+49 6221 54-4038