Rossmann returned to the UK and to the
University of Cambridge in 1958, where he worked with
Max Perutz on the structure of
hemoglobin as a research associate at the
MRC Laboratory of Molecular Biology. In 1964 Rossmann joined the faculty of the Department of Biological Sciences at Purdue University as an associate professor. He directed the Purdue
X-ray crystallography laboratory. He became full professor in 1967 and from 1978 held the chair of Hanley Distinguished Professor of Biological Sciences at the university. He also held a joint appointment in the department of biochemistry and adjunct positions in
Cornell University's Division of Biological Sciences and in
Indiana University's school of medicine. In 1970 his laboratory found the structure of
dogfish lactate dehydrogenase, one of the largest early proteins to be solved. In 1973 his group found the structure of
Glyceraldehyde 3-phosphate dehydrogenase, and Rossmann immediately realized that the binding site for the
NAD+ was very similar to the one in the lactate dehydrogenase. This is now called the
Rossmann fold. It is found in
enzymes (such as
dehydrogenases or
kinases) that bind molecules such as
ATP or NAD+/NADH. Rossmann then turned to viruses, spending a sabbatical in 1971 with
Bror Strandberg in
Uppsala, Sweden, working on the structure of the
satellite tobacco necrosis virus. From 1972 to 1980 Rossmann and his team worked on the
southern bean mosaic virus. This required developing new software and adapting existing software for
Fourier transforms. It was found that this virus had a similar "
jelly roll fold" to that found previously in the
tomato bushy stunt virus, which at the time was a surprise. The breakthrough nature of this result was such that the
National Science Foundation, which provided partial funding for the research, saw fit to organize a press conference, and the news travelled in the general press. This work laid the foundation for a molecular understanding of cell entry of
enteroviruses and for the development of capsid-binding inhibitors against a broad range of enteroviruses. After the success with the first cold virus, work was done on
alphaviruses and
flaviviruses. This work was made possible by more than one decade of studies on related mosquito borne
flaviviruses, including
dengue virus, using a combination of
cryo-electron microscopy and
X-ray crystallography. Rossmann also had a long-term interest in complicated viral machines. These are exemplified by
bacteriophage T4 and
nucleocytoplasmic large DNA viruses, also referred to as giant viruses. The determination of an atomic structure of Paramecium bursaria chlorella virus 1 that infects algae has opened up new possibilities for studying giant viruses at the atomic level. ==Life and hobbies==