Page 24 - Tyrosine-Based Bioconjugations - Jorick Bruins

Chapter 1
Scheme 4. General mechanism for reactions catalyzed by (mushroom) tyrosinase.89, 90
One of the most well-studied tyrosinases is the one found in the common mushroom (Agaricus Scheme 4. General mechanism for reactions catalyzed by (mushroom) tyrosinase.89, 90
bisporus), or mushroom tyrosinase (mTyr).91 This tyrosinase is expressed as a heterotetramer
comprising of two identical heavy chains of 43 kDa (H subunit) and two identical light chains of One of the most well-studied tyrosinases is the one found in the common mushroom (Agaricus
14 kDa (L subunit) (Figure 6).92 The tetram9e1r is stabilized by calcium ions between the two H
bisporus), or mushroom tyrosinase (mTyr). This tyrosinase is ex Scheme 4. General mechanism for reactions catalyzed by (mushroom) tyrosinase.
essed as a heterotetramer
subunits, which in the generation of the crystal structure was substituted for Holmium (III) ions comprising of two identical heavy chains of 43 kDa (H subunit) and two identical light chains of
One of the most well-studied tyrosinases is the one found in the common mushroom (Agaricus
(not depicted) to diminish re9p2ulsion between the negatively charged residues in the dimer 14 kDa (L subunit) (Figure 6). The tetramer is stabilized by calcium ions between the two H
bisporus), or mushroom tyrosinase (mTyr).91 This tyrosinase is expressed as a heterotetramer
interface (D336, D353, and E351 from one H subunit and the D312 side chain from the other).92 subunits, which in the generation of the crystal structure was substituted for Holmium (III) ions
comprising of two identical heavy chains of 43 kDa (H subunit) and two identical light chains of
Each H subunit has an interface92with one L subunit, stabilized by two salt bridges: H76 (H)–E139 (not de1p4ickDtead(L) stuobudnimt) i(nFiigsuhrer6e)p. ulTshieontetbraemtwereisenstatbhileizendebgyactailvceiulmy icohnas rbgeetwdeerenstihdeutewso iHn the dimer
92
(L) and sEu3b1un7it(sH, w)–hHic5h 6in(tLh)e. geIntewraatisonfoouf nthde tchryastailssotlrautcetudremwoans osumbsetirtiucteHd sfourbHuonlmitiurmet(aIIiIn) eiodnsits oxidativ9e2
interface (D336, D353, and E351 from one H subunit and the D312 side chain from the other).
(not depicted) to diminish repulsion between the negativ9e3ly charged residues in the dimer
activity suggesting the H subunit is the tyrosinase part, whereas the function of the L subunits Each H subunit has an interface with one L subunit, stabilized by two salt bridges: H76 (H)–E139
interface (D336, D353, and E351 from one H subunit and the D312 side chain from the other).92
is unknown. 92
(L) and E317 (H)–H56 (L). It was found that isolated monomeric H subunit retained its oxidative
Each H subunit has an interface with one L subunit, stabilized by two salt bridges: H76 (H)–E139
activity(Ls)uagngdeEs3t1i7n(gHt)–hHe56H(Ls)u. bIutnwiatsifsotuhndetthyartoisoilnaatesdempoanrotm, erwichHesruebausnithretafiunendcittisoonxiodafttivhee L subunits
activity suggesting the H subunit is the tyrosinase part,93 whereas the function of the L subunits is unknown.
is unknown.
92 93
8
p
9, 9
r
0
Figure 6. Crystal structure of mushroom tyrosinase (PDB: 2y9w).92 The blue and red subsections are the H subunits, the green and yellow subsections are L subunits, and the purp9l2e balls are the copper atoms.
Figure 6. Crystal structure of mushroom tyrosinase (PDB: 2y9w). The blue and red subsections are the H subunits, the green and yellow subsections are L subunits, and the purple balls are the copper atoms.
Figure 6. Crystal structure of mushroom tyrosinase (PDB: 2y9w).92 The blue and red subsections are the H subunits, the green and yellow subsections are L subunits, and the purple balls are the copper atoms.
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