Metalloproteins
Fundamental processes need metals
30% of all proteins bind metals
More than 40% of all enzymes need metal for function
Ex. For replication, DNA polymerase needs Fe-S cluser
Metals needed in humans
Bulk
Trace
Na, K, Hg, Ca
V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn
Metals constitute 1-2% of body weight
What do the metals do?
Metalloproteins
Dioxygen transport
Electron transport
Structural roles
Metalloenzymes
Communication Roles
Hydrolytic
Redox enzymes
Rearrangements
Fe3O4 magnetic "internal compass"
Na+, K+, Ca+ Cellular responses
Interaction with Nucleic Acids
Structure
Catalysis
Amino acids that regularly act as metal ligands in proteins are thiolates of cysteines, imidazoles of histidines, carboxylates of glutamic and aspartic acids, and phenolates of tyrosines
Redox-active metals
Iron, copper,
Oftenparticipate in electron transfer
Small redox-active metalloproteins facilitate electron-transfer reactions by alternately binding to specific integral membrane proteins that often contain several metal binding sites
Soluble redox-active metalloproteins
Iron-sulfur-cluster proteins
heme-binding cytochromes
blue-copper proteins