A Caltech Library Service

Metal Ion Dependence of Oligosaccharyl Transferase: Implications for Catalysis

Hendrickson, Tamara L. and Imperiali, Barbara (1995) Metal Ion Dependence of Oligosaccharyl Transferase: Implications for Catalysis. Biochemistry, 34 (29). pp. 9444-9450. ISSN 0006-2960. doi:10.1021/bi00029a020.

[img] PDF - Supplemental Material
See Usage Policy.

[img] PDF - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Oligosaccharyl transferase activity exhibits an absolute requirement for certain divalent metal cations. Studies with reconstituted enzyme suggest a preference for metal ions that can adopt an octahedral coordination geometry. In order to gain insight into the specific role of the metal cation in catalysis, we have investigated the influence of the metal cofactor on catalytic tumover of the tripeptide substrate Bz- Asn-Leu-Thr-NHMe (1) and a closely related sulfur-containing analog, Bz-Asn(yS)-Leu-Thr-NHMe (2). The metal ion substitution studies reveal that 1 is effectively tumed over in the presence of several metal ions (Mn^(2+), Fe^(2+), Mg^(2+), and Ca^(2+)). In contrast, 2 is only glycosylated in the presence of the thiophilic metal cations manganese and iron. When the enzyme is reconstituted with the oxophilic cations magnesium and calcium, 2 shows minimal substrate behavior. With the amide substrate 1, the distinct preference for manganese over magnesium may argue against direct coordination of the metal to the lipid-linked substrate pyrophosphate moiety. This fact, together with the comparative studies with asparagine- and thioasparagine-containing tripeptides, implicates the metal cofactor in a role that places it proximal to the peptide binding site.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Additional Information:© 1995 American Chemical Society. Published in print 25 July 1995. This work was supported by National Institutes of Health Grant GM39334, the Alfred P. Sloan Foundation, the Camille and Henry Dreyfus Teacher Scholar Program, and Zeneca, Inc. T.L.H. is supported by NIH Predoctoral Biotechnology Training Grant GM08346. Contribution no. 9046.
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Camille and Henry Dreyfus FoundationUNSPECIFIED
NIH Predoctoral FellowshipGM08346
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Chemistry and Chemical Engineering9046
Issue or Number:29
Record Number:CaltechAUTHORS:20180205-073724083
Persistent URL:
Official Citation:Metal Ion Dependence of Oligosaccharyl Transferase: Implications for Catalysis Tamara L. Hendrickson and Barbara Imperiali Biochemistry 1995 34 (29), 9444-9450 DOI: 10.1021/bi00029a020
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84662
Deposited By: Ruth Sustaita
Deposited On:05 Feb 2018 23:47
Last Modified:15 Nov 2021 20:21

Repository Staff Only: item control page