David Harker

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| name = David Harker

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| birth_date = {{birth date |1906|10|19}}

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| death_date = {{death date and age |1991|02|27 |1906|10|19}}

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| fields = Chemical crystallography

| workplaces = Polytechnic Institute of Brooklyn, Roswell Park Comprehensive Cancer Center, General Electric, Hauptman-Woodward Medical Research Institute

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| known_for = Harker–Kasper inequalities

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| awards = Gregori Aminoff Prize, 1984

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David Harker (October 19, 1906 – February 27, 1991) was an American medical researcher who according to The New York Times was "a pioneer in the use of X-rays to decipher the structure of critical substances in the life process of cells".[https://www.nytimes.com/1991/03/02/obituaries/dr-david-harker-84-a-pioneer-in-use-of-x-rays-in-cell-research.html?scp=1&sq=David%20Harker&st=cse New York Times:Obituaries:Dr. David Harker, 84, a Pioneer in Use of X-Rays in Cell Research, By WALTER SULLIVAN, Published: March 2, 1991][http://www.nap.edu/readingroom.php?book=biomems&page=dharker.html National Academies Press:David Harker, By Herbert A. Hauptman]

He is also well known for Harker–Kasper inequalities (statistical relationships between the phases of structure factors), which he devised in collaboration with John S. Kasper.

Harker made seminal discoveries in the field of chemical crystallography.{{Cite web |url=http://www.hwi.buffalo.edu/outreach/Pioneers/pioneers_2011.html |title=Hauptman-Woodward Medical Research Institute, PIONEERS OF SCIENCE AWARDEES - 2011 |access-date=2012-01-03 |archive-url=https://web.archive.org/web/20111003094740/http://www.hwi.buffalo.edu/outreach/Pioneers/pioneers_2011.html |archive-date=2011-10-03 |url-status=dead }}

His lab solved the structure of the pancreatic enzyme ribonuclease A,{{cite journal|vauthors=Kartha G, Bello J, Harker D | journal=Nature |title=Tertiary Structure of Ribonuclease |volume=213 |year=1967 |pages=862–865 |doi=10.1038/213862a0 |pmid=6043657 |bibcode=1967Natur.213..862K}} the third protein structure ever solved by protein crystallography.

Harker was a member of the National Academy of Sciences,

director of the protein structure program at the Polytechnic Institute of Brooklyn, director of the Center for Crystallographic Research at Roswell Park Comprehensive Cancer Center,[https://select.nytimes.com/gst/abstract.html?res=FB0910FE395415738DDDAB0A94DA405B848AF1D3&scp=10&sq=%22Dr.%20David%20Harker%22&st=cse New York Times:Crystal Research Planned, February 22, 1964] and the head of the crystallography division of General Electric.[https://www.nytimes.com/1949/01/03/archives/news-of-people-in-the-business-world.html?sq=David%2520Harker&scp=5&st=cse New York Times:NEWS OF PEOPLE IN THE BUSINESS WORLD, January 3, 1949] After retirement from Roswell Park in 1976, he joined the Hauptman-Woodward Medical Research Institute (HWI), then known as the Medical Foundation of Buffalo. He remained there until he died in 1991. His research interests while at HWI turned towards mathematical aspects of crystallography, including magnetic space groups and infinite polyhedra.

Harker was awarded the Gregori Aminoff Prize from the Swedish Academy in 1984. He was also elected president of the Electron Microscope Society of America.{{cite web|url=https://microscopy.org/past-presidents|title=MSA Past Presidents|publisher= Microscopy Society of America|accessdate= 15 April 2025}}