DNA is the molecule that carries the information of life in all living organisms. But on its own, this information is useless without proteins — the second key class of biomolecules. Proteins perform nearly all essential tasks in the cell: they build structures, transport molecules, regulate processes, and, most importantly, act as enzymes — catalysts that speed up chemical reactions necessary for life. Converting DNA-encoded information into proteins is one of nature’s most fundamental processes. You can think of DNA as the blueprint, and proteins as the builders and catalysts that bring the plan to life.

The Grininger lab focuses on proteins. We take a two-step approach: first, we study selected proteins to understand what they do and how they work in detail. Then, since proteins are natural catalysts, we explore how they can be reprogrammed to catalyze new reactions. For example, we rebuild enzymes to synthesize products of interest for biotechnology and health care.

Proteins are essential building blocks of life and are found in every living organism. They serve both structural and functional roles. Structurally, proteins can form stable frameworks. For example, the protein keratin provides strength to hair, nails, and skin, while the protein collagen is the main component of connective tissue. Functionally, proteins perform a wide range of tasks. They are responsible for binding and transporting molecules such as oxygen, vitamins, hormones, or other proteins. And, they are catalyzing chemical reactions. For example, enzymes such as hexokinase, citrate synthase, and malate dehydrogenase convert sugars and other nutrients into energy and essential metabolic intermediates. The enzyme ATP synthase drives the production of ATP, the universal energy carrier of the cell, by using the energy stored in a proton gradient. Other enzymes, including fatty acid synthase, are responsible for building up lipids, ensuring the proper balance of cellular energy and membrane components.

Proteins exist in many different architectures, and their structural complexity often mirrors the complexity of their functions. Some of the most remarkable examples are multidomain enzymes — large proteins in which several distinct catalytic units are connected within a single polypeptide chain. These domains work together to perform cascade or multistep reactions efficiently, passing intermediate products directly from one active site to the next. A prominent example of such systems are multienzyme complexes involved in fatty acid and polyketide synthesis. The Grininger Lab focuses on these multidomain proteins to understand how their internal organization enables complex reaction sequences, and to harness this principle for designing new catalytic pathways in biotechnology.

The Grininger Lab investigates the fascinating world of multidomain enzymes — complex molecular machines that can perform entire reaction sequences within a single protein scaffold. We aim to uncover how these enzymes are organized, how their catalytic domains communicate, and how they achieve the precise coordination required for efficient cascade reactions. A particular focus lies on large multienzyme systems such as fatty acid synthases, which serve as model systems to understand the structural and mechanistic basis of multistep catalysis. By combining biochemical, structural, and biophysical methods, we explore how architecture, flexibility, and dynamics define enzymatic function.

Building on this understanding, we apply protein engineering and design to reprogram multidomain enzymes for new purposes. By modifying their domain composition or catalytic properties, we investigate how these molecular assembly lines can be adapted to catalyze novel chemical transformations and produce compounds of technological or pharmaceutical relevance. In doing so, the Grininger Lab bridges fundamental research and applied biotechnology, aiming to develop efficient, sustainable, and enzyme-based alternatives to traditional chemical synthesis.