## 2 Materials and Methods
### Synthesis of Maltoligosaccharide-Modified PGA  
To a solution of PGA (12.4 mg, 0.082-unit mmol) in water (4.0 mL) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 12.0 mg, 0.082 mmol) and \(N\)-hydroxysuccinimide (NHS, 9.5 mg, 0.082 mmol) and the mixture was stirred at room temperature for 1 h. After Glc\(\gamma\)-NH\({}_{2}\) (100 mg, 0.082 mmol) was added to the resulting solution, the mixture was stirred at 60 \({}^{\circ}\)C for 24 h. The reaction solution was poured into methanol (300 mL) to precipitate the crude product. After the precipitate was isolated by centrifugation, the residue was dialyzed in a dialysis bag (molecular cut off: 3500) against water overnight. The lyophilized solution was concentrated and lyophilized to give maltooligosaccharide-modified PGA (11.8 mg) in 67.0% yield. \({}^{1}\)H NMR (D\({}_{2}\)O) \(\delta\) 1.86-2.01, 2.01-2.24 (br, \(\beta\)-CH\({}_{2}\) of PGA), 2.25-2.48 (br, \(\gamma\)-CH\({}_{2}\) of PGA), 3.35-4.09 (br, sugar protons of H2-H6), 4.10-4.27 (br, \(\alpha\)-CH of PGA), 5.18, 5.41 (br s, H1 of Glc). The the degree of substitution (DS) for a repeating \(\gamma\)-glutamic acid (GA) unit was determined by the integrated ratio of the \(\alpha\)-anomeric signal of Glc residues to the \(\alpha\)-CH\({}_{2}\) signal of PGA to be 5.7%.  
Synthesis of P2D-Amylase-Grafted PGAs by Thermostable GP-Catalyzed Copolymerization of D-Glucal with Glc-1-P  
A typical experimental procedure was as follows (run 2). A mixture of D-glucoseal (87.6 mg, 0.600 mmol), Glc-1-P (disodium salt, 182.4 mg, 0.600 mmol), and maltooligosaccharide-modified PGA (9 mg, nonreducing ends; 3.0 \(\upmu\)mol) in 0.20 mol/L Tris-acetate buffer (pH 6.9, 1.0 mL) containing KH\({}_{2}\)PO\({}_{4}\) (20.4 mg, 0.015 mmol) was stirred in the presence of thermostable GP (12 U) at 40 \({}^{\circ}\)C for 48 h. The precipitated product was isolated by centrifugation, washed with water, and lyophilized to obtain the P2D-amylose-grafted PGA (112.3 mg) in 58.3% yield based on amounts of the total 2 dGlc and Glc residues present in the reaction system. \({}^{1}\)H NMR (Figure 3, NaOD/D\({}_{2}\)O) \(\delta\) 1.70-1.90 (br, 2 dGlc-H\({}_{2\mathrm{ax}}\)), 1.90-2.00, 2.00-2.15 (br, \(\beta\)-CH\({}_{2}\) of PGA), 2.15-2.29 (br, 2 dGlc-H\({}_{2\mathrm{eq}}\)), 2.29-2.43 (br, \(\gamma\)-CH\({}_{2}\) of PGA), 3.30-4.00 (m, 2 dGlc-H3, 4, 5, 6 and Glc-H2, 3, 4, 5, 6), 4.00-4.27 (br, \(\alpha\)-CH of PGA), 5.25 (br s, \(\alpha\)(1\(\rightarrow\)4)-Glc-H1), 5.46 (br s, \(\alpha\)(1\(\rightarrow\)4)-2 dGlc-H1).  
Figure 3: \({}^{1}\)H NMR spectrum of P2D-amylose-grafted PGA (entry 2, Table 1) in NaOD/D\({}_{2}\)O.  
Synthesis of Amylose- and 2-Deoxyamylose-Grafted PGAs by Thermostable GP-Catalyzed Homopolymerization of Glc-1-P and D-Glucal, Respectively  
Amylose- and 2-deoxyamylose-grafted PGAs were synthesized by the thermostable GP-catalyzed polymerizations of Glc-1-P and D-glucal, respectively, using maltooligosaccharide-modified PGA according to the same procedure as above (runs 1 and 7). \({}^{1}\)H NMR of the amylose-grafted PGA (Figure S1, NaOD/D\({}_{2}\)O) \(\delta\) 1.87-1.99, 1.99-2.14 (br, \(\beta\)-CH\({}_{2}\) of PGA), 2.27-2.40 (br, \(\gamma\)-CH\({}_{2}\) of PGA), 3.40-3.98 (m, Glc-H\({}_{2}\), 3, 4, 5, 6), 4.10-4.20 (br, \(\alpha\)-CH of PGA), 5.25 (br rs, \(\alpha\)(1\(\rightarrow\)4)-Glc-H1). \({}^{1}\)H NMR of the 2-deoxyamylose-grafted PGA (Figure S2, NaOD/D\({}_{2}\)O) \(\delta\) 1.77-1.90 (br, 2 dGlc-H\({}_{2\text{ax}}\)), 1.90-2.00, 2.00-2.15 (br, \(\beta\)-CH\({}_{2}\) of PGA), 2.15-2.44 (br, 2 dGlc-H2\({}_{\text{eq}}\), \(\gamma\)-CH\({}_{2}\) of PGA), 3.35-4.00 (m, 2 dGlc-H3, 4, 5, 6 and Glc-H2, 3, 4, 5, 6), 4.00-4.33 (br, \(\alpha\)-CH of PGA), 5.18 (br s, \(\alpha\)(1\(\rightarrow\)4)-Glc-H1), 5.39 (br, \(\alpha\)(1\(\rightarrow\)4)-2 dGlc-H1).