The N-terminal domain of human holocarboxylase synthetase facilitates biotinylation via direct interaction with the substrate protein.
Human holocarboxylase synthetase shows a high degree of sequence homology in the catalytic domain with bacterial biotin ligases such as Escherichia coli BirA, but differs in the length and sequence of the N-terminus. Despite several studies having been undertaken on the N-terminal region of hHCS, the role of this region remains unclear. We determined the structure of the N-terminal domain of hHCS by limited proteolysis and showed that this domain has a crucial effect on the enzymatic activity. The domain interacts not only with biotin acceptor protein, but also with the catalytic domain of hHCS, as shown by nuclear magnetic resonance (NMR) experiments. We propose that the N-terminal domain of hHCS recognizes the charged region of biotin acceptor protein, distinctly from the recognition by the catalytic domain.
Lee
Chung-Kyung
CK
Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon-Gun, Chungbuk, Republic of Korea.
Cheong
Chaejoon
C
Jeon
Young Ho
YH
D001665:Binding Sites / Q000235:genetics; D019921:Biotinylation; D019731:Carbon-Nitrogen Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain / Q000235:genetics; D002918:Chymotrypsin / Q000378:metabolism; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D019286:Endopeptidase K / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D020860:Subtilisin / Q000378:metabolism
D002918:Chymotrypsin; D020860:Subtilisin; D019286:Endopeptidase K; D019731:Carbon-Nitrogen Ligases; C023312:holocarboxylase synthetases