National Center for Biotechnology Information NCBI NLM MEDLINE Molecular animals pubmed abstract nih national institutes of health national library of medicine models research support non-u.s. gov't ligands water / metabolism protein conformation water / chemistry anisotropy crystallization electrons binding sites heme / chemistry hydrogen bonding crystallography pmid:10512835 pmc1300496 doi:10.1016/s0006-3495(99)77056-6 j vojtechovský k chu i schlichting carbon monoxide / metabolism* x-ray / instrumentation x-ray / methods heme / metabolism histidine / chemistry histidine / metabolism metmyoglobin / chemistry* metmyoglobin / metabolism myoglobin / chemistry* myoglobin / metabolism oxygen / metabolism* protons whales