Table I. Sequence dependence of nascent chain glycosylation and photocross-linking to STT3.
| Construct | Photocross-linking | Glycosylation |
|---|---|---|
| NKT | − | + |
| NST | − | + |
| QKT | +++ | − |
| AKT | ++ | − |
| GKT | +++ | − |
| RKT | + | − |
| WKT | − | − |
| IKT | − | − |
| LKT | − | − |
| DKT | − | − |
| QKS | ++ | − |
| AKS | − | − |
| AKA | − | − |
| QKQ | − | − |
| NKQ | − | − |
| PQKT | + | − |
| QKTP | ++ | − |
| QKQSTKQ | − | − |
| KRQSTGK | − | − |
RNCs with various sequences in place of the NKT in the pPL-sK(NKT) nascent chain were prepared, targeted to microsomes, and photolyzed. In each case, translocation intermediates with different lengths of nascent chain were examined so that the probe was incorporated 67, 73, 81, 89, or 97 residues from the tRNA in parallel samples, except that NST nascent chains had an Asn (not a probe) located 68, 74, 82, 90, or 98 residues from the tRNA. KRQSTGK nascent chains had probes at 64 + 70, 70 + 76, 78 + 84, 86 + 92, or 94 + 100 residues from the P site, whereas KQSTK nascent chains had probes at 65 + 69, 71 + 75, 79 + 83, 87 + 91, or 95 + 99.