1NKR:
reference: Structure of the inhibitory receptor for human natural killer cells resembles haematopoietic receptors., Fan QR, Mosyak L, Winter CC, Wagtmann N, Long EO, Wiley DC, Nature 1997 Sep 4;389(6646):96-100. PMID: 9288975

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).