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Complex Formation between Copper and Organic Disulfides.

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a short time of being fed with Dyriscus secretion or cortexone
solutions per 0s. Cortexone has no action o n the beetle since
it is a hormone foreign to the insects.
___~
be arranged in five paired regions. Almost all odd nucleotides
appear in loops and unpaired regions. Probably the three
nucleotides in which the two tRNA's differ are also located in
loops.
Received: February 22nd, 1966
[Z 16511 IE]
German version: Angew. Chem. 78, 392 (1966)
The primary structures of the serine-specific tRNA's are very
different from that of the alanine-specific tRNA. The distances, however, between I, DimeG, and one of the UH2's are
the same. It is noteworthy that the distance between rT and
the C-C-A-end is also the same in the three tRNA's. The
sequence G-rT-$-C-G,
however, which has been considered as a possible constituent of all tRNA'sr41,is replaced
by G-rT-+-C-A
in serine-specific tRNA I.
[I J Communication XXI on Arthropod Defensive Substances. Communication XX: H . Schildknecht and W. F. Wenneis, Z.
Naturforsch., in press. The investigations were made possible by
financial support from the Deutsche Forschungsgemeinschaft.
We thank Messrs. Merck, Darmstadt, for a gift of cortexone.
Mr. H. Schaefein (Straubing) helped us by supplying water beetles.
[2] H. Schildknecht and K. Holoubek, Angew. Chem. 71,524 (1959).
[3 J L . Velluz and M. Legrand, Angew. Chem. 73,603 (196 1).
[4] L. F. Fieser and M. Fieser: Organische Chemie. Verlag
Chemie, Weinheim 1965, p. 1623.
[5] H . Blunck, Z. wiss. Zool. 117, 205 (1917).
Received: February 23rd, 1966
[Z 155/988 IEI
German version: Angew. Chem. 78, 392 (1966)
[I] Serine-specific transfer-ribonucleic acids, part VIII. - Part
VII : H . G. Zachau, D . Diitiing, F. Melchers, H. Feldmann, and
R . Thiebe in: Ribonucleic Acid - Structure and Function, Symposium of the Federation of European Biochemical Societies,
Vienna 1965. Pergamon Press, Oxford 1966, p. 21.
[2] We are indebted to Misses H . Heusinger, S . Notz, and G. Schulz
for expert technical assistance. The work was supported by grants
from the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie, and the Bundesministerium fur Wissenschaftliche Forschung.
[3] Abbreviations: tRNA = transfer ribonucleic acid; RNase =
ribonuclease; p and - are used to represent a phosphate residue;
A = adenosine; G = guanosine; C = cytidine; U = uridine; =
pseudouridine; UH2 = 4,5-dihydrouridine; rT = ribothymidine;
1= inodne; A', see text; MeC = 5-methylcytidine; AcC = N(6)acetylcytidine; DimeG = N(2)-dimethylguanosine; OMeG = 2'0-methylguanosine; OMeU = 2'-0-methyluridine.
[4] R . W. Holley, J. Apgar, G. A.Everett, J. T . Madison, M . Marquisee, s. H . Merrill, J . R . Penswick, and A . Zamir, Science
(Washington) 147, 1462 (1965).
[5] See, for example, F. Melchers and H. G. Zachau, Biochim.
biophysica Acta 91, 559 (1964).
[6] W. Karau and H. G. Zachau, Biochem. biophysica Acta 91,
549 (1964).
[7] Note added in proof: (March 16th, 1966): Investigations by
high-resolution mass spectrometry suggest that A* from serine
tRNA is an N(6)-isopentenyladenosine ( K . Biemann and S.Tsukanawa, personal communication). Nuclear magnetic resonance
studies in collaboration with J. Sonnenbichler showed that two
methyl groups are located on C-3 and the double bond is
between C-2 and C-3 of the side chain.
Nucleotide Sequences of two Serine-Specific
Transfer Ribonucleic Acids [1,21
By Prof. H. G. Zachau, Dr. D. Diitting,and Dr. H. Feldmann
Institut fur Genetik der Universitat Koln (Germany)
Structural studies o n transfer-ribonucleic acids (tRNA's [31)
recently entered a new phase when Holley et al. [41 established
the primary structure of an alanine-specific tRNA.We have
been able for the first time to elucidate the nucleotide sequences of two tRNA's specific for the same amino acid, i.e.
of the two main serine-specific tRNA's from brewer's yeast.
Thus the second complete nucleotide sequence of a nucleic
acid can now be reported. In earlier stages of this work, F.
Melchers [51 and W. Karau 6 1 made important contributions.
+
The serine-specific tRNA's were split with pancreatic RNase
and TpRNase into oligonucleotides, the structures of which
were determined by further enzymatic degradation. Sequences of up to 25 nucleotides could be constructed by comparing the two sets of oligonucleotides. In addition to the partial digestion with TI-RNase 141, the elucidation of the complete sequences required partial digestion with pancreatic
RNase, a second partial splitting of large oligonucleotide
fragments, and sequential degradation with snake venom
phosphodiesterase of oligonucleotides obtained by partial TIRNase digestion.
Dime
I
~G-G-C-A-A-C-U-U-G-G-C-C-G-A-G-U-G-G-~-A-A-G-G-C-G-A-A-A-G-A-~U-I-G-A-A*-A-~C-U-U-UAc
1
HzOMe Hz
1
;
OMe
Me
1
U-G-G-G-C-U-U-U-G-C-C-C-G-C-G-C-A-G-G-rT-~C-G-A-G-U-C-C-U-G~-A-G-U-U-G-U-C-G-C~-A- -
I
-
Serine-specific tRNA I and I1 from brewer's yeast.
Upper line: Nucleotide sequence common to both t R N A s .
Middle line: Continuation of the upper line for t R N A 11.
Lower line: Continuation of the upper line for tRNA I.
The two serine-specific tRNA's differ only in three nucleotides
(which are underlined in the formula). The differences may
originate from transitions in the t R N A cistrons. The chain
length (84 nucleotides) and the probable anticodon sequence
I-G-A are the same in both tRNA's.
Thirteen odd nucleotides occur in the serine-specific tRNA's.
N(6)-acetyl-Cp, A*p (the structure of which is not yet completely known[71), and the two nucleotides methylated in the
ribose have been found in tRNA-sequences for the first time.
Models of the secondary structure of the two serine-specific
tRNA's were constructed using only the principle of maximal
base pairing. They show that ca. 60% of the nucleotides can
422
-
Complex Formation between Copper
and Organic Disulfides
By Doz. Dr. P. Hemmerich
Anorganisch-Chemisches lnstitut der Universitat Basel
(Switzerland) and
Prof. Dr. H. Beinert and Dr. T. Vanngard
Institute for Enzyme Research, University of Wisconsin
Madison, Wisconsin (U.S.A.)
In general, mercaptide complexes of copper(l1) are unstable,
because of the reaction 11,21
a
F
2Cu2++ 2RS~ ( C U I I S R ) ' i ' 2Cu' + (RS)2
(a)
Equilibrium p, however, can be displaced towards the right
only in those cases where
Angew. Chem. internat. Edit.
Vol. 5 (1966)
1 No. 4
a) the Cu+ generated is stabilized by Cuhpecific Iigands,
most easily by a n excess of RS- (to form colorless
(CUISR),~~]),and where
b) the reaction is kinetically feasible, i.e. the hypothetical
(CuIISR)+ must either be able to dissociate into radicals
( + CU’. + RS.) or to react with itself [ + ( C U S R ) ~ ~ ~ ] .
The formation of a binuclear complex ( 1 ) 141 is clearly the
easiest way to fulfil condition b). In such a complex, Cull
mercaptide and Cur disulfide are isoelectronic and chemically
indistinguishable.
Of prime importance in this context is the affinity for CuI of
digonal sulfur, as found in the very stable, colorless CUTmethionine chelate [31. In aqueous solution cystamine also
forms a chelate with Cuc which, however, is deep violet in color and is maximally developed after liberation of one Hf per
Cu[31. This complex may be formed according to Eq. (b) in
agreement with structure ( I ) or according to Eq. (c) leading
to structure (2), which corresponds to the structure of a
similar complex arising from thiomalic acid and Cu*+ as
found by Klotr et al. 151.
(RSSRH2)2++ ~ C U 7+2 [CUI~(RS)
* (CUI’SR~]~++
2H’
(b)
(1)
2(RSSRH2)2++ 8Cu+ + [(CuIRS)4CuII]2++ 3Cu2++ 4H+ (c)
(2)
These equations differ essentially in the concomitant formation of Cu2+. Hence we followed the formation of Cu2+
during pH-titration of cystamine in the presence of Cu+ by
quantitative EPR spectroscopy in the solid (-170 “C) and
liquid phase. In the pH-region 3-7 we found an increase in
CuII from 1 % 161 to not more than 7 ”/, of total Cu. At p H 7,
one mole of H f per mole Cu is liberated and the maximum
color is reached with an extinction of ca. 5 x 103 cm-1 per
mole C u W The reaction, therefore, must follow Eq. (b) t o
more than 90 %, i.e. the contribution of a complex (2) cannot
be more than 10%. If the color were due to this complex ex-
clusively, the molar extinction per Cu” would be as high as
lo5 cm-1, which is unlikely.
At pH 7, the violet complex disproportionates irreversibly
with precipitation of Cu(0H)z. If, on the other hand, a
mercaptide-specific reagent, ArHg+, is added, oxidoreduction
ensues. In both cases the stoichiometric amount of C U ~ is
+
found by EPR spectroscopy.
Hence, we take these results as strong evidence for theexistence
of copper mercaptides of type ( I ) with R-L = CHzCHzNH2.
Their strong color points to extensiveelectron delocalization in
the - presumably diamagnetic - cluster CugCu. Their potential biological importance stems from the fact that certain Cu
chromophores in redox enzymes, which may contain cyst(e)ine sulfur, are found to contain 2 or more Cu atoms (cytochrome oxidase, coeruloplasmine), which are redox-active,
but not fully detectable by EPR spectroscopy 181. Binuclear
complexes of type ( I ) might explain this behavior when
kinetically stabilized by a protein environment, whilst 0and N-ligdnds cannot be expected to allow for redox activity
in Cu complexes unless accompanied by molecular rearrangements 131.
Received: February 16th. 1966
[Z 157/2IEl
German version: Angew. Chem. 78,449 (1966)
.
~~
-. .
[I] Cu+ and Cu2f indicate free solvated ions, while CuI and CuII
indicate oxidation states in any ligand field.
[2] I. M . Kolthoff and W. Sticks, J. Amer. chem. SOC.73, 1728
(1951).
131 P. Hemmerich in P. Aisen, W. E. Blumberg, and J. Peisach:
The Biochemistry of Copper. Academic Press, New York 1966,
in press.
[4] D . H . Busch, D . C . Jicha, M . S. Thompson, W. J. Wrathall,
and E. Blinn, J. Amer. chem. SOC.86, 3648 (1965).
[51 I. M . Klotz, G . H . Czerlinski, and H. A . Fiess, J. Amer. chem.
SOC.80, 2920 (1958).
[6] The 1yo CuII present at the beginning represents the inevitable impurity of the starting material CuI(CH3CN)4C104;
P. Hemmerich and C . Sigwart, Experientia 19, 488 (1963).
[71 This order of magnitude corresponds to the chromophore of
deeply colored Cu-proteins; cf. W. E. Blumberg, W. G. Levine,
S. Maroglis, and J. Peisach, Biochem. biophys. Res. Commun.
15, 277 (1954).
[8] Cf. H . Beinert and G. Palmer in T. E. King, H. S. Mason, and
M . Morrison: Oxidases and Related Redox Systems. Wiley, New
York 1965, Vol. 11, pp. 567-585; B. G. Malmstrom, ibid. Vol. I,
p. 207; B. F. van Gelder and E. C . Slater, Biochim. biophysica
Acta 73, 663 (1963).
C O N F E R E N C E REPORTS
Association of Aliphatic Hydroxy Compounds
in n-Heptane
G . Geiseler, Leipzig (Germany)
Infrared-spectroscopicand thermodynamic studies of the association of isomeric alcohols, oximes, carboxylic acids, and
hydroperoxides derived from n-heptane and n-octane have
shown that chains and three-dimensional structures are preferably formed by monofunctionally associating isomers, but
that only cyclic dimers and trimers are formed from bifunctionally associating isomers 111.
Indirect insight into the mode of association can also be obtained from the thermodynamic excess functions, as has been
found in studies of binary mixtures of octanols or octanone
oximes with n-heptane. The excess free energy determined
from phase equilibria depends significantly on the position of the functional group in the chain. However, the
excess enthalpy determined calorimetrically provides much
more information: the excess enthalpy has a maximum at the
same mole fraction (Xhept % 0.55) for all the oximes. From
this it must be concluded that substantially the same type of
order applies to all the (undiluted) oximes; structural differences have only slight effect.
Angew. Chem. internat. Edit.
1 Vol. 5
(1966)
No. 4
The excess enthalpy has a maximum at xhept NN 0.65 for 1and 2-octanol, but for 3- and 4-octanol the maximum is
shifted to Xhept M 0.75. Clearly the type of order is different
for the two alcohols (when undiluted or in concentrated solution). For the first two it is assumed that the molecules form
linear associates, but for the second that they are joined in
parallel.
The excess entropies, which pass through a minimum, show
a completely analogous behavior. They indicate that in the
region up t o xhept M 0.95 the associtates behave o n the average as stoichiometrically uniform components and that on
admixture with n-heptane they force a definite type of order
on it. Only in highly dilute solution are the associates broken;
this is particularly evident for the alcohols as the excess
entropy then becomes positive.
[Lecture at Hamburg, November 9th, 1965, and at
Kiel, November 11th, 19651
[VB 974/281 IE]
German version: Angew. Chem. 78, 395 (1966)
[I] G . Geiseler, Angew. Chem. 77, 352 (1965); Angew. Chern.
internat. Edit. 4, 367 (1965); ,,Monofunctionally” and “bifunctionally” associating molecules differ by the number of
atoms with acceptor effect in the associating group; the first type
has one, the second two such atoms.
423
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