Structure determination of murine mitochondrial carbonic anhydrase V at 2.45-A resolution: implications for catalytic proton transfer and inhibitor design.

Boriack-Sjodin, P.A.; Heck, Robert W.; Laipis, Philip J.; Silverman, David N.; Christianson, D.W.

doi:10.1073/pnas.92.24.10949

Cited by 105 publications

(94 citation statements)

References 32 publications

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“…Tyrosine residues have been shown to be important for proton transfer in manganese superoxide dismutase (39) and carbonic anhydrase V (40,41), and in proton abstraction from a steady-state intermediate in thymidylate synthase (42). In superoxide dismutase, the tyrosine is part of a hydrogen-bonded network that connects the active site with water molecules and ionizable residues, and mutational studies suggest that it is a proton donor within this network (39).…”

Section: Discussionmentioning

confidence: 99%

“…In superoxide dismutase, the tyrosine is part of a hydrogen-bonded network that connects the active site with water molecules and ionizable residues, and mutational studies suggest that it is a proton donor within this network (39). Tyr131 in carbonic anhydrase V participates as a proton shuttle between the solution and a zinc-bound water molecule at the active site; in this case, its functional pK a is reduced to Ϸ9 by virtue of its location in an electropositive region of the protein (40,41). In thymidylate synthase, the data suggested that the tyrosine could abstract a proton from the reaction intermediate or serve to polarize or orient a water molecule to perform this reaction (42).…”

Section: Discussionmentioning

confidence: 99%

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Proton uptake by bacterial reaction centers: The protein complex responds in a similar manner to the reduction of either quinone acceptor

Mikšovská

Schiffer

Hanson

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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In bacterial photosynthetic reaction centers, the protonation events associated with the different reduction states of the two quinone molecules constitute intrinsic probes of both the electrostatic interactions and the different kinetic events occurring within the protein in response to the light-generated introduction of a charge. The kinetics and stoichiometries of proton uptake on formation of the primary semiquinone Q A ؊ and the secondary acceptor QB ؊ after the first and second flashes have been measured, at pH 7.5, in reaction centers from genetically modified strains and from the wild type. The modified strains are mutated at the L212Glu and͞or at the L213Asp sites near Q B; some of them carry additional mutations distant from the quinone sites (M231Arg 3 Leu, M43Asn 3 Asp, M5Asn 3 Asp) that compensate for the loss of L213Asp. Our data show that the mutations perturb the response of the protein system to the formation of a semiquinone, how distant compensatory mutations can restore the normal response, and the activity of a tyrosine residue (M247Ala 3 Tyr) in increasing and accelerating proton uptake. The data demonstrate a direct correlation between the kinetic events of proton uptake that are observed with the formation of either Q A ؊ or QB ؊ , suggesting that the same residues respond to the generation of either semiquinone species. Therefore, the efficiency of transferring the first proton to Q B is evident from examination of the pattern of H ؉ ͞QA ؊ proton uptake. This delocalized response of the protein complex to the introduction of a charge is coordinated by an interactive network that links the Q ؊ species, polarizable residues, and numerous water molecules that are located in this region of the reaction center structure. This could be a general property of transmembrane redox proteins that couple electron transfer to proton uptake͞release reactions.proton transfer ͉ site-specific mutagenesis ͉ membrane protein ͉ water channel R eaction centers (RCs) from photosynthetic bacteria convert light energy into chemical free energy. These transmembrane complexes are composed of three protein subunits. Two of them, L and M, are fully embedded in the photosynthetic membrane and carry all of the pigments and cofactors present in the RC. The three-dimensional structures of the RCs from two species, Rhodobacter sphaeroides and Rhodopseudomonas viridis, are known at 2.2 Å (1) and 2.0 Å (2) resolution, respectively. The initial capture of energy is achieved through a transmembrane charge separation between the primary electron donor-a bacteriochlorophyll dimer (''P''), situated near the periplasmic side of the protein, and a system of two quinones located near the cytoplasmic side. The primary quinone acceptor, Q A , is bound in a relatively hydrophobic region of the M subunit. The formation of the transient P ϩ Q A Ϫ state occurs by electron transfer from P via H A (an intermediate bacteriopheophytin electron carrier) and is followed by electron donation to Q B , the secondary quinone acceptor. Q A functi...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Proton uptake by bacterial reaction centers: The protein complex responds in a similar manner to the reduction of either quinone acceptor

Mikšovská

Schiffer

Hanson

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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“…Furthermore, it is interesting to compare the residue 131 region among different isozymes. For example, although Tyr-131 is located in a short ␣-helix in murine mitochondrial carbonic anhydrase V, this helix undergoes an Ϸ2-Å segmental shift compared with the corresponding helix of CA II (11). In human carbonic anhydrase I (7), it does not.…”

Section: A Fierke Personal Communication)mentioning

confidence: 99%

Crystal structure of the secretory form of membrane-associated human carbonic anhydrase IV at 2.8-Å resolution

Stams

Nair

Okuyama

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

139

118

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It has recently been demonstrated that the C-terminal deletion mutant of recombinant human carbonic anhydrase IV (G267X CA IV) converts the normally glycosylphosphatidylinositol-anchored enzyme into a soluble secretory form which has the same catalytic properties as the membrane-associated enzyme purified from human tissues. We have determined the three-dimensional structure of the secretory form of human CA IV by x-ray crystallographic methods to a resolution of 2.8 Å. Although the zinc binding site and the hydrophobic substrate binding pocket of CA IV are generally similar to those of other mammalian isozymes, unique structural differences are found elsewhere in the active site. Two disufide linkages, Cys-6-Cys-11G and Cys-23-Cys-203, stabilize the conformation of the N-terminal domain. The latter disulfide additionally stabilizes an active site loop containing a cis-peptide linkage between Pro-201 and Thr-202 (this loop contains catalytic residue Thr-199). On the opposite side of the active site, the Val-131-Asp-136 segment adopts an extended loop conformation instead of an ␣-helix conformation as found in other isozymes. Finally, the C terminus is surrounded by a substantial electropositive surface potential, which is likely to stabilize the interaction of CA IV with the negatively charged phospholipid headgroups of the membrane. These structural features are unique to CA IV and provide a framework for the design of sulfonamide inhibitors selective for this particular isozyme.

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“…The most recently identified class of carbonic anhydrase, the ␥-class (24), is represented by the prototype Cam from the archaeon Methanosarcina thermophila (2). Even though sequences encoding putative ␥-class carbonic anhydrases have been found in prokaryotes from both the Bacteria and Archaea domains (2, 52), Cam is the only ␥-class enzyme that has been biochemically characterized (2,3,58).Crystal structures for five ␣-class mammalian isozymes (CA I to V) (10,16,17,23,33,38,54) and the ␣-class enzyme from N. gonorrhoeae (26) reveal a monomer in which the dominating secondary feature is an antiparallel ␤-sheet. The ␥-class Cam is remarkably distinct from the ␣-class carbonic anhydrases in that it is a homotrimer in which each monomer adopts a novel left-handed ␤-helix fold (28, 36).…”

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confidence: 99%

“…Crystal structures for five ␣-class mammalian isozymes (CA I to V) (10,16,17,23,33,38,54) and the ␣-class enzyme from N. gonorrhoeae (26) reveal a monomer in which the dominating secondary feature is an antiparallel ␤-sheet. The ␥-class Cam is remarkably distinct from the ␣-class carbonic anhydrases in that it is a homotrimer in which each monomer adopts a novel left-handed ␤-helix fold (28, 36).…”

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confidence: 99%

Structural and Kinetic Characterization of an Archaeal β-Class Carbonic Anhydrase

et al. 2000

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The ␤-class carbonic anhydrase from the archaeon Methanobacterium thermoautotrophicum (Cab) was structurally and kinetically characterized. Analytical ultracentrifugation experiments show that Cab is a tetramer. Circular dichroism studies of Cab and the Spinacia oleracea (spinach) ␤-class carbonic anhydrase indicate that the secondary structure of the ␤-class enzymes is predominantly ␣-helical, unlike that of the ␣-or ␥-class enzymes. Extended X-ray absorption fine structure results indicate the active zinc site of Cab is coordinated by two sulfur and two O/N ligands, with the possibility that one of the O/N ligands is derived from histidine and the other from water. Both the steady-state parameters k cat and k cat /K m for CO 2 hydration are pH dependent. The steady-state parameter k cat is buffer-dependent in a saturable manner at both pH 8.5 and 6.5, and the analysis suggested a ping-pong mechanism in which buffer is the second substrate. At saturating buffer conditions and pH 8.5, k cat is 2.1-fold higher in H 2 O than in D 2 O, consistent with an intramolecular proton transfer step being rate contributing. The steady-state parameter k cat /K m is not dependent on buffer, and no solvent hydrogen isotope effect was observed. The results suggest a zinc hydroxide mechanism for Cab. The overall results indicate that prokaryotic ␤-class carbonic anhydrases have fundamental characteristics similar to the eukaryotic ␤-class enzymes and firmly establish that the ␣-, ␤-, and ␥-classes are convergently evolved enzymes that, although structurally distinct, are functionally equivalent.The thermophilic archaeon Methanobacterium thermoautotrophicum obtains energy for growth by the reduction of CO 2 to CH 4 and is also an obligate chemolithoautotroph; thus, this organism has a high demand for CO 2 . Carbonic anhydrase, a zinc-containing enzyme catalyzing the reversible hydration of carbon dioxide (equation 1)is expected to play an important role in the growth of M. thermoautotrophicum and may have several functions, including transporting HCO 3 Ϫ into the cell and providing CO 2 or HCO 3 Ϫ to enzymes that utilize these substrates. Based on sequence comparisons, carbonic anhydrases belong to three genetically distinct classes (␣, ␤, and ␥) which appear to have independent origins (24). The most extensively studied enzymes are those from the ␣-class, which is composed primarily of mammalian carbonic anhydrases, but also includes enzymes from the green alga Chlamydomonas reinhardtii (19,20) and the prokaryote Neisseria gonorrhoeae (13). The ␤-class enzymes are abundant in C 3 and C 4 monocotyledenous and dicotyledenous plants and green unicellular algae (24, 43), where they are essential for photosynthetic CO 2 fixation (6). The most recently identified class of carbonic anhydrase, the ␥-class (24), is represented by the prototype Cam from the archaeon Methanosarcina thermophila (2). Even though sequences encoding putative ␥-class carbonic anhydrases have been found in prokaryotes from both the Bacteria and Archaea domains (2...

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Structure determination of murine mitochondrial carbonic anhydrase V at 2.45-A resolution: implications for catalytic proton transfer and inhibitor design.

Cited by 105 publications

References 32 publications

Proton uptake by bacterial reaction centers: The protein complex responds in a similar manner to the reduction of either quinone acceptor

Proton uptake by bacterial reaction centers: The protein complex responds in a similar manner to the reduction of either quinone acceptor

Crystal structure of the secretory form of membrane-associated human carbonic anhydrase IV at 2.8-Å resolution

Structural and Kinetic Characterization of an Archaeal β-Class Carbonic Anhydrase

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