The present invention is directed to a coil unit of a single-acting linear engine. A first node connects to a first input of the first selector, a second node connects to a first input of the second selector, a third node connects to a second input of the first selector, and a fourth node connects to a second input of the second selector. The decarboxylation is carried out in the range greater than 240 and up to 275\xb0 C. The first dummy pattern and the second dummy pattern can be disposed around a side of the main pattern. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing and using the polypeptides.