How was Johann Deisenhofer awarded the Noble Prize?

Name: Johann Deisenhofer. 
Country: Germany and the United States.
Date of Birth: 13 September 1943.
The subject of Study: X-ray diffraction bacteria, Photosynthesis reaction center.
Noble Prize Year: Nobel Prize for Chemistry in 1988 for their research on the structure of certain proteins that are essential to photosynthesis.