UAAs  unnatural amino acids  Rd  rubredoxin  EPR  electron paramagnetic resonance  Az  azurin  SOR  superoxide reductase  PDB  protein data bank  6-PGLac  6-phosphogluconolactonase  H-bond  hydrogen-bond  NIR  nitrite reductase  ET  electron transfer  3SCC  three stranded coiled coil  Bpy-Ala  (2,2′-bipyridinine-5-yl)alanine  CcO  cytochrome c oxidase  N2OR  nitrous oxidase reductase  XANES  X-ray absorption near-edge structure  DF  Due Ferri  4-AP  4-amino-phenol  POP  prolyl oligopeptidase  ee  enantiomeric excess  HCO  heme-copper oxidase  NOR  nitric oxide reductase  MnP  manganese peroxidase  Mb  myoglobin  RFQ-rR  freeze-quench resonance Raman  CcP  Cyt c peroxidase  BMC  microcompartment  CYP  cytochrome P450  TON  turnover number  TDHC  tetradehydrocorrin  NB  nitrobindin  RCM  ring-closing metathesis  ROMP  ring-opening metathesis polymerization  SAV  steptavidin  NCS  neocarzinostatin  BLG  -Lactoglobulin  HSA  human serum albumin  BSA  bovine serum albumin  ITC  isothermal titration calorimetry  AldO  alditol oxidase  FAD  flavin adenine dinucleotide  MP  microperoxidase  HB  heme-binding  GTL  Geobacillus thermocatenulatus lipase  4NPA  4-nitrophenyl acetate  LmrR  Lactococcal multidrug resistance Regulator  ABTS  2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt  mCPBA  meta-chloroperbenzoic acid  Fd  ferredoxin  Fld  flavodoxin  HTHP  hexameric Tyr-coordinated heme protein  AFM  atomic force microscopy  TEM  transmission electron microscopy  MRI  magnetic resonance imaging  Metalloproteins  Metalloenzymes  Protein design  Multiple active sites  Biocatalysts