{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T04:23:02Z","timestamp":1789446182848,"version":"build-2803163510"},"reference-count":45,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5835","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[2007,7,13]]},"abstract":"<jats:p>\n                    The extreme toxicity of organomercury compounds that are found in the environment has focused attention on the mechanisms of action of bacterial remediating enzymes. We describe facile room-temperature protolytic cleavage by a thiol of the Hg-C bond in mercury-alkyl compounds that emulate the structure and function of the organomercurial lyase\n                    <jats:italic>MerB<\/jats:italic>\n                    . Specifically, the tris(2-mercapto-1-\n                    <jats:italic>t<\/jats:italic>\n                    -butylimidazolyl)hydroborato ligand [Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ], which features three sulfur donors, has been used to synthesize [Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgR alkyl compounds (R = methyl or ethyl) that react with phenylthiol (PhSH) to yield [Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgSPh and RH. Although [Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgR compounds exist as linear two-coordinate complexes in the solid state,\n                    <jats:sup>1<\/jats:sup>\n                    H nuclear magnetic resonance spectroscopy indicates that the complexes exist in rapid equilibrium with their higher-coordinate [\u03ba\n                    <jats:sup>2<\/jats:sup>\n                    -Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgR and [\u03ba\n                    <jats:sup>3<\/jats:sup>\n                    -Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgR isomers in solution. Facile access to a higher-coordinate species is proposed to account for the exceptional reactivity of [Tm\n                    <jats:sup>\n                      Bu\n                      <jats:sup>t<\/jats:sup>\n                    <\/jats:sup>\n                    ]HgR relative to that of other two-coordinate mercury-alkyl compounds.\n                  <\/jats:p>","DOI":"10.1126\/science.1144314","type":"journal-article","created":{"date-parts":[[2007,7,12]],"date-time":"2007-07-12T17:03:59Z","timestamp":1184259839000},"page":"225-227","source":"Crossref","is-referenced-by-count":110,"title":["Cleaving Mercury-Alkyl Bonds: A Functional Model for Mercury Detoxification by\n                    <i>MerB<\/i>"],"prefix":"10.1126","volume":"317","author":[{"given":"Jonathan G.","family":"Melnick","sequence":"first","affiliation":[{"name":"Department of Chemistry, Columbia University, New York, NY 10027, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerard","family":"Parkin","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Columbia University, New York, NY 10027, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","doi-asserted-by":"publisher","DOI":"10.1080\/10408440600845619"},{"key":"e_1_3_1_3_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp0529826"},{"key":"e_1_3_1_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0278-6915(02)00043-1"},{"key":"e_1_3_1_5_2","unstructured":"For other examples of Hg(II) binding to zinc finger proteins see ( 5 6 )."},{"key":"e_1_3_1_6_2","doi-asserted-by":"publisher","DOI":"10.1006\/taap.2001.9132"},{"key":"e_1_3_1_7_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.toxlet.2005.10.018"},{"key":"e_1_3_1_8_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr050353m"},{"key":"e_1_3_1_9_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0168-6445(03)00046-9"},{"key":"e_1_3_1_10_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar00177a006"},{"key":"e_1_3_1_11_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi0259148"},{"key":"e_1_3_1_12_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi049669z"},{"key":"e_1_3_1_13_2","unstructured":"Cys 96 Cys 117 and Cys 159 are highly conserved in MerB from other sources and are essential for activity; Cys 160 is only weakly conserved and is not essential ( 10 )."},{"key":"e_1_3_1_14_2","unstructured":"[Tm R ] ligands have recently been effectively used to provide compounds that mimic aspects of the chemistry relevant to the active sites of sulfur-rich zinc enzymes and proteins. See for example ( 14 )."},{"key":"e_1_3_1_15_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr0206263"},{"key":"e_1_3_1_16_2","unstructured":"Abbreviations: Me = methyl Et = ethyl Ph = phenyl Bu t = t -butyl R = alkyl or aryl X = monovalent inorganic ligand Hmim Bu t = 1- t -butylimidazole-2-thione."},{"key":"e_1_3_1_17_2","unstructured":"There is also a long-range Hg\u00b7\u00b7\u00b7S secondary interaction (3.3 \u00c5) that is perpendicular to the two primary Hg-C and Hg-S bonds."},{"key":"e_1_3_1_18_2","first-page":"2987","volume":"2002","year":"2002","unstructured":"J. L. White, J. M. Tanski, D. Rabinovich, J. Chem. Soc. Dalton Trans.2002, 2987 (2002).","journal-title":"J. Chem. Soc. Dalton Trans."},{"key":"e_1_3_1_19_2","doi-asserted-by":"publisher","DOI":"10.1002\/1099-0682(200205)2002:5<1235::AID-EJIC1235>3.0.CO;2-6"},{"key":"e_1_3_1_20_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi049662h"},{"key":"e_1_3_1_21_2","unstructured":"[Tm Bu t ]HgCH 2 CN is obtained from the reaction of [Tm Bu t ]K EtHgCl and KBH 4 in MeCN."},{"key":"e_1_3_1_22_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(95)05395-6"},{"key":"e_1_3_1_23_2","unstructured":"Two-coordination at mercury is also common for thiolate compounds ( 23 )."},{"key":"e_1_3_1_24_2","first-page":"323","volume":"38","year":"1990","unstructured":"J. G. Wright, M. J. Natan, F. M. MacDonnell, D. M. Ralston, T. V. O'Halloran, Prog. Inorg. Chem.38, 323 (1990).","journal-title":"Prog. Inorg. Chem."},{"key":"e_1_3_1_25_2","doi-asserted-by":"publisher","DOI":"10.1002\/ejic.200300907"},{"key":"e_1_3_1_26_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic00104a029"},{"key":"e_1_3_1_27_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(97)00485-3"},{"key":"e_1_3_1_28_2","unstructured":"Intermediate three-coordinate \u201cT-shaped\u201d geometries are also known. For example the approximately linear coordination observed for [pzTp]HgMe [169(2)\u00b0] is supplemented by a secondary Hg\u00b7\u00b7\u00b7N interaction ( 28 )."},{"key":"e_1_3_1_29_2","doi-asserted-by":"publisher","DOI":"10.1071\/CH9871609"},{"key":"e_1_3_1_30_2","unstructured":"{[\u03ba 3 -N(CH 2 CH 2 PPh 2 ) 3 ]HgPh} + reacts with ArSH but the reaction has been proposed to involve initial dissociation of N(CH 2 CH 2 PPh 2 ) 3 and subsequent formation of [HN(CH 2 CH 2 PPh 2 ) 3 ] + which is the active reagent in the protolytic cleavage rather than the thiol ( 25 )."},{"key":"e_1_3_1_31_2","unstructured":"Half-life \u2248 15 min for [Tm Bu t ]HgEt with [PhSH] = 0.1 M."},{"key":"e_1_3_1_32_2","doi-asserted-by":"publisher","DOI":"10.1007\/430_031"},{"key":"e_1_3_1_33_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja01579a025"},{"key":"e_1_3_1_34_2","unstructured":"Thus whereas Me 2 Hg reacts slowly with certain biologically related thiols to cleave one of the Hg-C bonds cleavage of the second Hg-CH 3 bond could not be achieved ( 34 )."},{"key":"e_1_3_1_35_2","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1521-3773(20000218)39:4<784::AID-ANIE784>3.0.CO;2-Z"},{"key":"e_1_3_1_36_2","unstructured":"Calculations suggest that the increased facility of protolytic cleavage of the Hg-C bond upon increasing coordination number is a consequence of an associated increase in negative charge on the carbon ( 36 )."},{"key":"e_1_3_1_37_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp061852"},{"key":"e_1_3_1_38_2","unstructured":"See supporting material on Science Online."},{"key":"e_1_3_1_39_2","unstructured":"The related methimazole complex [(Hmim Me )HgMe](NO 3 ) has been reported ( 39 )."},{"key":"e_1_3_1_40_2","doi-asserted-by":"publisher","DOI":"10.1139\/v83-267"},{"key":"e_1_3_1_41_2","unstructured":"The nature of the final mercury product has not been identified."},{"key":"e_1_3_1_42_2","unstructured":"The positive charge on the complex could also inhibit protolytic cleavage. In this regard the corresponding reaction of neutral [mim Bu t ]HgR with PhSH was also investigated but the reaction yielded PhSHgR as a result of preferential protonation of the nitrogen atom of the [mim Bu t ] ligand. Moreover the two-coordinate neutral compound PhSHgR is inert to excess PhSH at room temperature."},{"key":"e_1_3_1_43_2","unstructured":"Addition of Hmim Bu t to {[Hmim Bu t ]HgR} + in the absence of PhSH does not result in cleavage of the Hg-C bond. Rather the 1 H NMR spectrum shows that Hmim Bu t merely binds reversibly as indicated by the observation that the mercury-methyl signal for {[Hmim Bu t ]HgMe} + shifts from \u03b4 0.48 to 0.62 in the presence of Hmim Bu t ."},{"key":"e_1_3_1_44_2","unstructured":"Although MerB obtained from E. coli (R831b) has three cysteines at the active site only two of these are highly conserved in MerB from other sources ( 10 ). It is therefore possible that a residue other than cysteine could also facilitate the protolytic cleavage. In this regard studies on a model system indicate that carboxylate bases may also serve to promote protolytic cleavage of Hg-C bonds ( 44 )."},{"key":"e_1_3_1_45_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00259a061"},{"key":"e_1_3_1_46_2","unstructured":"Supported by NSF grant CHE-0619638 which enabled the acquisition of an x-ray diffractometer and by NIH grant GM046502. Complete crystallographic data have been deposited in the Cambridge Crystallographic Database Centre (accession numbers 648324 to 648331)."}],"container-title":["Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.science.org\/doi\/pdf\/10.1126\/science.1144314","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,10]],"date-time":"2024-01-10T04:40:45Z","timestamp":1704861645000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.science.org\/doi\/10.1126\/science.1144314"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,7,13]]},"references-count":45,"journal-issue":{"issue":"5835","published-print":{"date-parts":[[2007,7,13]]}},"alternative-id":["10.1126\/science.1144314"],"URL":"https:\/\/doi.org\/10.1126\/science.1144314","relation":{"has-review":[{"id-type":"doi","id":"10.3410\/f.1089779.542919","asserted-by":"object"}]},"ISSN":["0036-8075","1095-9203"],"issn-type":[{"value":"0036-8075","type":"print"},{"value":"1095-9203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,7,13]]}}}