Synonymy of Etiennea Matile-Ferrero with Hemilecanium Newstead (Hemiptera: Coccidae), based on morphology of adult females, adult males and first-instar nymphs, and description of a new potential pest species from the Ryukyu Archipelago, Japan

The genus Etiennea Matile‐Ferrero is synonymized with Hemilecanium Newstead (Hemiptera: Coccidae). We base this decision on a morphological comparative study of adult females, adult males and first‐instar nymphs (crawlers), including a phylogenetic analysis. We recovered a sister group relationship between the type species of the two genera, Etiennea villiersi Matile‐Ferrero and Hemilecanium theobromae Newstead; that is, each was more closely related to the other than either was to other species in their respective genera. All species hitherto included in Etiennea are transferred to Hemilecanium: H. bursera (Hodgson & Kondo) comb. nov., H. cacao (Hodgson) comb. nov., H. candelabra (Hodgson) comb. nov., H. capensis (Hodgson) comb. nov., H. carpenteri (Newstead) comb. nov., H. cephalomeatus (Hodgson) comb. nov., H. combreti (Hodgson) comb. nov., H. ferina (De Lotto) comb. nov., H. ferox (Newstead) comb. nov., H. gouligouli (Hodgson) comb. nov., H. halli (Hodgson) comb. nov., H. kellyi (Brain) comb. nov., H. madagascariensis (Hodgson) comb. nov., H. montrichardiae (Newstead) comb. nov., H. multituberculum (Hodgson) comb. nov., H. petasus (Hodgson) comb. nov., H. sinetuberculum (Hodgson) comb. nov., H. tafoensis (Hodgson) comb. nov., H. ulcusculum (Hodgson) comb. nov., and H. villiersi (Matile‐Ferrero) comb. nov. Keys to the adult females of all 26 species and known adult males and first‐instar nymphs are provided. The adult males and first‐instar nymphs of H. theobromae Newstead and E. villiersi Matile‐Ferrero are for the first time fully described and illustrated. One new potential pest species of Hemilecanium, H. uesatoi Kondo & Hardy sp. nov., which was collected on three islands of the Ryukyu Archipelago, Japan, is described and illustrated based on the adult female, adult male and first‐instar nymph. We discuss evidence that H. uesatoi is a new introduction to the Ryukyu Archipelago. The first‐instar nymphs of Hemilecanium can be divided into two distinct morphological groups, the petasus group and the theobromae group.     

Ten new species of caddisflies (Insecta: Trichoptera) from the Baltic amber

Ten new species of caddisflies of the families Polycentropodidae (nine) and Molannidae (one) are described from the Eocene Baltic amber: Holocentropus peregrinator sp. nov., H. proximorepertus sp. nov., H. dugoi sp. nov., H. fundamentalis sp. nov., H. telergon sp. nov., Plectrocnemia varigoria sp. nov., P. synthesia sp. nov., P. novokshonovi sp. nov., Nyctiophylax valideturbidus sp. nov., and Molanna okraina sp. nov.     

Influence of the 3'-UTR-length of mKIAA cDNAs and their Sequence Features to the mRNA Expression Level in the Brain

We have previously described the sequence features of 1500 mouseKIAA (mKIAA) genes in comparison with those of human KIAA genes(Okazaki, N., Kikuno, R., Inamoto, S., Hara, Y., Nagase, T.,Ohara, O., and Koga, H. 2002, DNA Res., 9, 179–188; Okazaki,N., Kikuno, R., Ohara, R., Inamoto, S., Aizawa, H., Yuasa, S.,Nakajima, D., Nagase, T., Ohara, O., and Koga, H. 2003, DNARes., 10, 35–48; Okazaki, N., Kikuno, R., Ohara, R., Inamoto,S., Koseki, H., Hiraoka, S., Saga, Y., Nagase, T., Ohara, O.,and Koga, H. 2003, DNA Res., 10, 167–180; and Okazaki,N., F-Kikuno, R., Ohara, R., Inamoto, S., Koseki, H., Hiraoka,S., Saga, Y., Seino, S., Nishimura, M., Kaisho, T., Hoshino,K., Kitamura, H., Nagase, T., Ohara, O., and Koga, H. 2004,DNA Res., 11, 205–218). To validate the orthologous relationshipbetween mKIAA and KIAA genes in detail, we examined their chromosomalpositions and evolutionary rate of synonymous substitutionsand confirmed that >93% of the mKIAA/KIAA gene pairs areorthologous. During the sequence analysis of mKIAA genes, wefound that 3'-untranslated region (3'-UTR) lengths of mKIAAand KIAA genes are extremely long. In the meanwhile, we havealso examined the tissue-specific expression of 1700 mKIAA genesusing cDNA microarray and verified predominantly their expressionin adult brain (Koga, H., Yuasa, S., Nagase, T., Shimada, K.,Nagano, M., Imai, K., Ohara, R., Nakajima, D., Murakami, M.,Kawai, M., Miki, F., Magae, J., Inamoto, S., Okazaki, N., Ohara,O. 2004, DNA Res., 11, 293–304). To connect these twoevidences, we statistically analysed the relationship betweenthem by using the mKIAA genes. Consequently, a positive correlationwas observed between the 3'-UTR lengths and the relative expressionintensities in adult brain. Furthermore, we searched sequenceelements in the 3'-UTR possibly related with their expressionand found some candidates regarding the brain-specific expression.     

Descriptions of five new species of Haplostylus (Mysidacea-Crustacea) from South West Australia

Five new species, Haplostylus flagelliforma sp. nov., H.similissp. nov., H.multispinosus sp. nov., H.uthupus sp. nov. and H.disparsp. nov., are described from the south-west coast of Australia.These new species are distinguishable from each other and fromthe other allied species by the structure of the pleopods ofthe male, and by the armature of the telson and the uropods.     

Taxonomic notes on the genus Holepyris (Hymenoptera: Bethylidae) from Korea with descriptions of six new species

Six new species of the genus Holepyris (Hymenoptera: Bethylidae: Epyrinae) from Korea are described: H. brevicarinatus sp. nov., H. crinitus sp. nov., H. dimidiatus sp. nov., H. longicephalus sp. nov., H. mucro sp. nov. and H. multo sp. nov. They are described with illustrations of male genitalia and the biometric measurement data. A key to the Korean species of Holepyris based on males is provided.     

Schistosoma mansoni:The Circulating Cathodic Antigen Forms an Abundant Product of 41/42 kDa in the Urine of Infected Patients

Abdeen, H. H., Attallah, A.-F. M., El-Mohamady, H. I., Harrison, R. A., and Mansour, M. M. 1998.Schistosoma mansoni: The circulating cathodic antigen forms an abundant product of 41/42 kDa in the urine of infected patients.Experimental Parasitology90, 286–289.     

Book Reviews

Book Reviewed in this article:
DFG-ökotoxikologie von Pflanzenschutzmitteln-Mitteilungen I, 1994
Bennett, W. F. (ed) .
Arit, K. Enzian, S. and Pallut, B.
Ettl, H., G. Gärtner .
Blume, H.-P., Felix-Henningsen, P., Fischer, W. R., Frede, H.- G., Horn, R., Stahr, K.
Mielke, H.
Goodman, R.N., Novacky, A.J.
Karg, W., Freier, B.
Müller, R. et al .
Landsmann, J., Casper, R.
Shigo, A. L.
P etrini , O. and G. B. O uelletre (eds), Host Wall Alterations by Parasitic Fungi .     

Four New Species of the Genus Hemicriconemoides (Nematoda:Criconematidae)

Four new species of the genus Hemicriconemoides (H. californianus n.sp., H. taiwanensis n.sp., H. annulatus n. sp., and H. nitida n.sp.) are described. The range of total length of H. mangiferae is increased on the basis of specimens collected in Israel, Observations on H. mangiferae and H. litchi support the validity of H. litchi as distinct from H. mangiferae.     

Screening for antiproliferative activity of six southern Brazilian species of Hypericum

The crude methanolic extracts of six species of Hypericum growing in southern Brazil (Hypericum caprifoliatum Cham. & Schlecht., H. carinatum Griseb., H. connatum Lam., H. myrianthum Cham. & Schlecht., H. polyanthemum Klotzsch ex Reichardt and H. ternum A. St. Hil.) were screened for their antiproliferative activity against two cell lines (HT-29 human colon carcinoma cells and H-460 non-small cell lung carcinoma). The most active crude extracts were those from H. caprifoliatum, H. myrianthum and, to a lesser extent, from H. connatum. All plants were submitted to fractionation with solvents in increasing polarity and re-assayed for the two cell lines used previously, as well as U-373 human malignant glioma cells. The most active fractions were the hexane fractions obtained from H. caprifoliatum, H. myrianthum and H. ternum.     

Lecithoceridae (Lepidoptera: Gelechioidea) of New Guinea: Part II. Hamatina gen. nov., with descriptions of four new species

This is the second part in a series of taxonomic studies on the family Lecithoceridae (Lepidoptera: Gelechioidea) of New Guinea. A new genus, Hamatina gen. nov., is described, based on the type species, H. hemitoma (Diakonoff), comb. nov., and four new species are described: H. nabangae sp. nov., H. robdevosi sp. nov., H. jembatana sp. nov., and. iriana sp. nov. A key to four allied genera is given. Adults, heads, labial palpi, wing venations, and the male genitalia are illustrated.     

GABAA receptors display association of gamma 2-subunit with alpha 1- and beta 2/3-subunits.

Recombinant GABAA (gamma-aminobutyrate-Type A) receptors that are sensitive to benzodiazepine receptor ligands can be generated by coexpression of alpha-, beta-, and gamma 2-subunit cDNAs (Pritchett, D. B., Sontheimer, H., Shivers, B. D., Ymer S., Kettenmann, H., Schofield, P. R., and Seeburg, P. H. (1989) Nature 338, 582-585; Pritchett, D. B., Lüddens, H., and Seeburg, P. H. (1989) Science 245, 1389-1392; Malherbe, P., Sigel, E., Baur, R., Perssohn, E., Richards, J. G., and Mohler, H. (1990) J. Neurosci. 10, 2330-2337). However, in brain tissue, only alpha- and beta-subunit proteins have so far been detected. To identify the size and distribution of the gamma 2-subunit protein in brain tissue, polyclonal antibodies were prepared against two synthetic peptides corresponding to amino acids 1-15 and 336-350 of the cDNA-derived rat gamma 2-subunit sequence. On Western blots, both anti-gamma 2-subunit antisera selectively labeled a 43-kDa protein. gamma 2-Subunit immunoreactivity was detected immunohistochemically in various brain regions, e.g. in the olfactory bulb, cerebral cortex, islands of Calleja, hippocampus, substantia nigra, and cerebellum. Immunoprecipitation with both antisera identified the gamma 2-subunit immunoreactivity in 40 and 50% of the native GABAA receptors purified from bovine and rat brains, respectively. Monoclonal antibody bd24 selectively recognizes the alpha 1-subunit, whereas bd17 recognizes both the beta 2- and beta 3-subunits (Ewert, M., Shivers, B. D., Lüddens, H., Mohler, H., and Seeburg, P. H. (1990) J. Cell Biol. 110, 2043-2048). Since either of these monoclonal antibodies (bd17 and bd24) precipitated approximately 90% of the GABAA receptors, the gamma 2-subunit is frequently associated with the alpha 1-subunit and the beta 2- and/or beta 3-subunit in vivo.     

Taxonomic review of Hemistola Warren, 1893 from China,with descriptions of seven new species (Lepidoptera: Geometridae,Geometrinae)

The genus Hemistola Warren from China is reviewed, and seven new species are described: H. viridimargo, sp. nov., H. glauca sp. nov., H. asymmetra sp. nov., H. arcilinea sp. nov., H. flavifimbria sp. nov., H. orbiculosoides sp. nov. and H. stueningi sp. nov. Two species, acyra and christinaria, are transferred from Hemistola to Maxates and Comostola, respectively: Maxates acyra comb. nov. and Comostola christinaria comb. nov. Including the 25 species previously known from China, a total of 32 species is now recorded. All Chinese species are redescribed. Generic characters based on all species are summarized. Illustrations of adults and genitalia are presented.     

Alternating zinc fingers in the human male-associated protein ZFY: HX3H and HX4H motifs encode a local structural switch

The two-finger repeat in the human male-associated protein ZFY provides a model for comparative 2D-NMR studies of classical and variant Zn fingers. This repeat is defined in part by an alternation in spacing between consensus (HX3H) and variant (HX4H) histidine spacings. To investigate the effects of a "switch" between alternative histidine spacings, we have designed an HX3H analogue of a representative HX4H domain of known structure [ZFY-6; Kochoyan, M., Havel, T., Nguyen, D. T., Dahl, C. E., Keutmann, H. T., & Weiss, M. A. (1991) Biochemistry 30, 3371-3386]. The HX3H analogue (designated ZFY-switch) forms a tetrahedral Co2+ complex whose thermodynamic stability is similar to that of the parent peptide. 2D-NMR studies demonstrate that ZFY-switch and ZFY-6, although similar in overall structure, exhibit significant local changes near the site of deletion. Whereas the HX4H site in the native finger forms a nonstandard loop, the HX3H site in ZFY-switch folds as a 3(10) extension of the C-terminal alpha-helix, as observed in the NMR solution structure of a consensus HX3H domain [Lee, M. S., Gippert, G. P., Soman, K. V., Case, D. A., & Wright, P. E. (1989) Science 245, 635-637] and in the crystal structure of a representative Zn finger-DNA complex [Pavletich, N. P., & Pabo, C. O. (1991) Science 252, 809-817]. We propose that variant histidine spacings (HX3H and HX4H) encode a local switch between alternative surface architectures with implications for models of protein-DNA recognition.     

Modeling the cellular basis of altered excitation-contraction coupling in heart failure

Ca transients measured in failing human ventricular myocytes exhibit reduced amplitude and slowed relaxation [Beuckelmann, D.J., Nabauer, M., Erdmann, E., 1992. Intracellular calcium handling in isolated ventricular myocytes from patients with terminal heart failure. Circulation 85, 1046-1055; Gwathmey, J.K., Copelas, L., MacKinnon, R., Schoen, F.J., Feldman, M.D., Grossman, W., Morgan, J.P., 1987. Abnormal intracellular calcium handling in myocardium from patients with end-stage heart failure. Circ. Res. 61, 70-76; Kaab, S., Nuss, H. B., Chiamvimonvat, N., O'Rourke, B., Pak, P.H., Kass, D.A., Marban, E., Tomaselli, G.F., 1996. Ionic mechanism of action potential prolongation in ventricular myocytes from dogs with pacing-induced heart failure. Circ. Res. 78(2); Li, H.G., Jones, D.L., Yee, R., Klein, G.J., 1992. Electrophysiologic substrate associated with pacing-induced hert failure in dogs: potential value of programmed stimulation in predicting sudden death. J. Am. Coll. Cardiol. 19(2), 444-449; Vermeulen, J.T., McGuire, M.A., Opthof, T., Colonel, R., Bakker, J.M.T.d., Klopping, C., Janse, M.J., 1994. Triggered activity and automaticity in ventricular trabeculae of failing human and rabbit hearts. Cardiovasc. Res. 28, 1547-1554.] and blunted frequency dependence [Davies, C.H., Davia, K., Bennett, J.G., Pepper, J.R., Poole-Wilson, P.A., Harding, S.E., 1995. Reduced contraction and altered frequency response of isolated ventricular myocytes from patients with heart failure. Circulation, 92, 2540-2549; Hasenfuss, G., Reinecke, H., Studer, R., Meyer, M., Pieske, B., Holtz, J., Holubarsch, C., Posival, H., Just, H., Drexler, H., 1994. Relation between myocardial function and expression of sarcoplasmic reticulum Ca-ATPase in failing and nonfailing human myocardium. Circ. Res. 75, 434-442; Hasenfuss, G., Reinecke, H., Studer, R., Pieske, B., Meyer, M., Drexler, H., Just, H., 1996. Calcium cycling proteins and force-frequency relationships in heart failure. Basic Res. Cardiol. 91, 17-22; Monte, F.D., O'Gara, P., Poole-Wilson, P.A., Yacoub, M., Harding, S.E., 1995. Cell geometry and contractile abnormalities of myocytes from failing human left ventricle. Cardiovasc. Res. 30, 281-290; Philips, P.J., Gwathmey, J.K., Feldman, M.D., Schoen, F.J., Grossman, W., Morgan, J.P., 1990. Post-extrasystolic potentiation and the force-frequency relationships: differential augmentation of myocardial contractility in working myocardium from patients with end-stage heart failure. J. Mol. Cell. Cardiol. 22, 99-110; Pieske, B., Hasenfuss, G., Holubarsch, C., Schwinger, R., Bohm, M., Just, H., 1992. Alterations of the force-frequency relationship in the failing human heart depend on the underlying cardiac disease. Basic Res. Cardiol. 87, 213-221.]. Analyses of protein levels in these failing hearts reveal that the SR Ca-ATPase is down-regulated on average by 50% and that the Na/Ca exchanger is up-regulated on average by a factor of two. In this paper, we test the hypothesis that this altered pattern of expression of Ca handling proteins is sufficient to account for changes in excitation-contraction coupling properties measured experimentally at the cellular level. To do this, we present an integrated model of excitation-contraction coupling in the guinea pig ventricular cell. The model is used to determine the effects of SR Ca-ATPase down-regulation and Na/Ca exchanger up-regulation on action potential duration, Ca transient shape and amplitude, and isometric force. Model analyses demonstrate that changes in Ca handling proteins play a direct and critical role in prolongation of action potential duration, and in reduction of contractile force in heart failure.     

Subunit Composition and Substrate Specificity of a MOF-containing Histone Acetyltransferase Distinct from the Male-specific Lethal (MSL) Complex

Human MOF (MYST1), a member of the MYST (Moz-Ybf2/Sas3-Sas2-Tip60) family of histone acetyltransferases (HATs), is the human ortholog of the Drosophila males absent on the first (MOF) protein. MOF is the catalytic subunit of the male-specific lethal (MSL) HAT complex, which plays a key role in dosage compensation in the fly and is responsible for a large fraction of histone H4 lysine 16 (H4K16) acetylation in vivo. MOF was recently reported to be a component of a second HAT complex, designated the non-specific lethal (NSL) complex (Mendjan, S., Taipale, M., Kind, J., Holz, H., Gebhardt, P., Schelder, M., Vermeulen, M., Buscaino, A., Duncan, K., Mueller, J., Wilm, M., Stunnenberg, H. G., Saumweber, H., and Akhtar, A. (2006) Mol. Cell 21, 811–823). Here we report an analysis of the subunit composition and substrate specificity of the NSL complex. Proteomic analyses of complexes purified through multiple candidate subunits reveal that NSL is composed of nine subunits. Two of its subunits, WD repeat domain 5 (WDR5) and host cell factor 1 (HCF1), are shared with members of the MLL/SET family of histone H3 lysine 4 (H3K4) methyltransferase complexes, and a third subunit, MCRS1, is shared with the human INO80 chromatin-remodeling complex. In addition, we show that assembly of the MOF HAT into MSL or NSL complexes controls its substrate specificity. Although MSL-associated MOF acetylates nucleosomal histone H4 almost exclusively on lysine 16, NSL-associated MOF exhibits a relaxed specificity and also acetylates nucleosomal histone H4 on lysines 5 and 8.     

Book Reviews

Book reviewed in this article:
Lenné, J. M., A world list of fungal diseases of tropical pasture species.
Jahn, H., Pilze an Bäumen: Saprophyten und Parasiten die an Holz wachsen. 2., von H. R einartz und M. S chlag neubearbeitete und erweiterte Auflage.
Evans, W. H., und J. M. Graham, Deutsche Übersetzung von R. S chlögl , Struktur und Funktion biologischer Membranen.     

Eine Methode zur Prüufung innertherapeutisch wirkender Fungizide

Abstract

Burnett, J. H.: Fundamentals of Mycology. Edward Arnold, London, 1968. 546 S., 175 Abb., 96 Tab., 9 Taf., geb., £ 6 10 s. Reviewed by W. Kühnel.

Smith, R. F. (Ed.): Annual Review of Entomology. Vol. 14, Annual Reviews Inc., Palo Alto, 1969, 478 S., 6 Abb., 25 Tab., 6 Tafeln, geb. $ 9.00. Reviewed by R. Fritzsche.

Somogyi, J. C.; Francois, A. C.: Antibioties in Agriculture. Basel, S. Karger AG, 1968, 208 S., 28 Abb., 50 Tab., brosch., sF/DM 57,—. Reviewed by H. J. Müller.

Metlitskh, B. L.; Ozeretskovskaya, O. L.: Plant immunity: Biochemical aspects of plant resistance to parasitic fungi. Plenum Press, Now York, 1968, 114 S., 9 Abb., 18 Tab., geb., 12,50 $. Reviewed by H. Wolffgang.     

Buchbesprechungen

Morris, C. J. O. R.; Morris, P.: Separation methods in biochemistry. London, Sir Isaac Pitman & Sons Ltd., 1964, 887 S., 155 Abb., Leinen, £ 5, 15 s. Reviewed by H. Wolffgang.

Neuman, M.: Vade-mecum des antibiotiques et agents chimiothérapiques anti-infectieun. Paris, Librairie Maloine G. Doin et Cie Editeurs, 1962, 410 S., 8 Abb.; 15 Tab., Karton. 40,00 NF. Reviewed by Thren.

Umbreit, W. W.: Modern microbiology. San Francisco und London, W. H. Freeman and Company, 1962, 507 S., 307 Abb., Leinen, 48 s. Reviewed by H. J. Müller.

Gold, V.: pH-Measurements. Their theory and practice. London, Methuen & Co. Ltd., 1963, 125 S., 11 Abb., Leinen, 10 s 6 d. Reviewed by H. Wolffgang.

Horsfall, J. G. (Ed.): Annual review of phytopathology. Vol. 1, Palo Alto, Annual Reviews, Inc., 1963, 469 S., 6 Abb., Leinen, 9,00 $. Reviewed by M. Schmiedeknecht.

Rubin, B. A.; Artsikhovskaya, Ye. V.: Biochemistry and physiology of plant immunity. Oxford, Pergamon Press, 1963, IX und 358 S., 68 Abb., Leinen, £ 5. Reviewed by H. Wolffgang.

Nord, F. F. (Ed.): Advances in Enzymology. Vol. 24, New York und London, Interscience Publishers a division of John Wiley & Sons, 1962, 572 S., 23 Abb., Leinen, 120 s. Reviewed by H. Wolffgang.

Nord, F. F. (Ed.): Advances in Enzymology. Vol. 25, New York und London, Interscience Publishers a division of John Wiley & Sons, 1963, 565 S., 56 Abb., Leinen, 115 s. Reviewed by H. Wolffgang.

Forbes, J.: A laboratory manual for histology. 2. Aufl., New York, Fordham University Press, 1961, 132 S., 3 Abb., brosch., 3,00 $. Reviewed by J. H. Scharf.

Guaoliumi, P.: Las Plagas de la Caña de Azucar en Venezuela. Bd. 1 und 2, Maracay/Yenezuela, Ministerio de Agricultura y Cria Centro de Investigaciones Agronoinicas, 1962, 850 S., 212 Abb., 14 ganzs. Farbtafeln, brosch., 8,00 $. Reviewed by G. Fröhlich.

Clifton, C. E. (Ed.): Annual review of microbiology. Vol. 17, Palo Alto, Annual Reviews, Inc., 1963, 628 S., 19 Abb., Leinen, 9,00 $. Reviewed by K. Naumann.

Ramschandran, G. N. (Ed.): Aspects of protein structure. Proceedings of a symposium held in Madras 14–18 January 1963 and organized by the University of Madras. London und New York, Academic Press, 1963, 380 S., 130 Abb., Leinen, 84 s. Reviewed by P. Hermann.     

Solution studies of staphylococcal nuclease H124L. 2. 1H, 13C, and 15N chemical shift assignments for the unligated enzyme and analysis of chemical shift changes that accompany formation of the nuclease-thymidine 3',5'-bisphosphate-calcium ternary complex.

Accurate 1H, 15N, and 13C chemical shift assignments were determined for staphylococcal nuclease H124L (in the absence of inhibitor or activator ion). Backbone 1H and 15N assignments, obtained by analysis of three-dimensional 1H-15N HMQC-NOESY data [Wang, J., Mooberry, E.S., Walkenhorst, W.F., & Markley, J. L. (1992) Biochemistry (preceding paper in this issue)], were refined and extended by a combination of homo- and heteronuclear two-dimensional NMR experiments. Staphylococcal nuclease H124L samples used in the homonuclear 1H NMR studies were at natural isotopic abundance or labeled randomly with 2H (to an isotope level of 50%); nuclease H124L samples used for heteronuclear NMR experiments were labeled uniformly with 15N (to an isotope level greater than 95%) or uniformly with 13C (to an isotope level of 26%). Additional nuclease H124L samples were labeled selectively by incorporating single 15N- or 13C-labeled amino acids. The chemical shifts of uncomplexed enzyme were then compared with those determined previously for the nuclease H124L.pdTp.Ca2+ ternary complex [Wang, J., LeMaster, D. M., & Markley, J.L. (1990) Biochemistry 29, 88-101; Wang, J., Hinck, A.P., Loh, S. N., & Markley, J.L. (1990) Biochemistry 29, 102-113; Wang, J., Hinck, A.P., Loh, S.N., & Markley, J.L. (1990) Biochemistry 29, 4242-4253]. The results reveal that the binding of pdTp and Ca2+ induces large shifts in the resonances of several amino acid segments. These chemical shift changes are interpreted in terms of changes in backbone torsion angles that accompany the binding of pdTp and Ca2+; changes at the binding site appear to be transmitted to other regions of the molecule through networks of hydrogen bonds.