Understanding protein structure and function is critical in health and disease as well as in many biotechnological systems and productions. In the Protein Science lab we explore how proteins are shaped, how they interact with other proteins, their function or downstream effect, and their impact in a biological context. 

The brown bear project

We use the hibernating brown bear as a source for identifying new human therapies. During summer and autumn, the brown bears prepare for winter by accumulating a huge fat mass – they become extremely obese. Then during winter time, the bears hibernate for a six-month long hibernation period without any physical activity. Despite exposure to these significant risk factors for many diseases in humans, diseases such as diabetes, cardiovascular diseases, bone and muscle loss, and bed sores have not been observed in the bears. Indeed, the bears switch their metabolism to fat burning, while preserving muscle and bone mass during hibernation. By comparing the molecular conditions of blood and tissue samples taken during hibernation in winter with samples taken during the active summer period, we try to identify the biochemical regulators involved in the remarkable physiological adaptions for hibernation and inactivity. We hypothesize that such endocrine regulators, preserving health in hibernating bears, likely also have relevance for maintaining health in obese or inactive humans and thus that the hibernating Scandinavian brown bear serves as a novel translational model for development of new human therapies.

Calmodulinopathy project

Calcium-ions constitute a signal for the initiation of many cellular processes that translate into vital physiological functions, including heartbeat generation and brain signal transduction. The pivotal role of calcium-ions necessitates a means to accurately and rapidly measure changes in the intracellular Ca-concentration. For this purpose, cells utilize the Ca-sensing protein calmodulin. Calmodulin senses changes in Ca-concentration and relays this information to more than 300 cellular interaction partners. Calmodulin therefore plays an equally critical role in every cell as the calcium ion itself.

In 2012, we reported the first mutation in the protein calmodulin in patients (Nyegaard et al, 2012). These individuals suffered from severe cardiac arrhythmia and sudden cardiac arrest. Since this initial discovery, we and others have further linked other mutations in calmodulin to life-threathening heart arrhythmias. These findings are surprising, given the fundamental role of calmodulin in decoding cellular calcium signaling. Our aim is to identify the full pathological spectrum of calmodulin mutations, and describe the underlying molecular mechanisms for these.

Using biophysical methods we have demonstrated that most of these pathogenic calmodulin mutations have impaired Ca2+ binding affinity. Further, using specialized 2D binding assays we find altered binding to interaction partners. In particular, calmodulin mutations affect the regulation of Ca2+-channels in the plasma membrane and in the sarcopalsmic reticulum. In addition to binding assays, we use fluorescence calcium imaging to visualize the altered gating of these channels. 

Proteomics

As part of the MS core facilities, the Protein Chemistry group has well established pipeline for bottom-up shotgun proteomics using Orbitrap technology (QE-HF, Thermo) and intact protein analysis with MALDI-TOF MS (Autoflex, Bruker). The group offers service to both internal and external projects on widely varying topics such as differential expression studies, proteome characterization and quantification of single species and highly complex samples, characterization of non-tryptic protein hydrolysates, and middle-down/up proteomics. The group seeks to explore new territories for MS-based proteomics and has a large interest in proteomics for food and feed application. The group is involved in various food and feed-related projects where especially the PROVIDE project(Innovation Fund Denmark), which seeks to valorize protein rich side stream from industrial production by combining proteomics, bioinformatics, functional characterization, and proteolysis by fermentation and enzymatic hydrolysis. The group is also interested in exploring new directions within experimental and computational proteomics that will be of great scientific and industrial value.

Methods

The Protein Science lab works with a large range of methods within biochemistry, biophysics, cell biology, and bioinformatics.

We routinely work with:

• Protein expression and purification from E. coli and insect cultures
• Biophysical protein characterization using fluorescence spectroscopy, thermophoresis, fluorescence anisotropy, isothermal titration calorimetry, circular dichroism
• Biochemical protein analysis including SDS-PAGE, Western blotting
• Automated liquid handling robot
• Mass-spectrometry where the group hosts the institute MS core facilities equipped with MALDI-TOF-MS, LC-HRMS, nLC-ESI-MS/MS, and GC-MS/MS
• Cell culture assays
• Spinning-disk confocal fluorescence microscopy of living cells, including calcium imaging