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<DIV align=center><FONT face=Arial size=2><FONT size=4>Seminarios DQIAQF -
INQUIMAE, Martes 23 de noviembre de 2010 - 13
h</FONT>s.<BR> <BR>Aula de Seminarios INQUIMAE - DQIAQF<BR>Facultad de
Ciencias Exactas y Naturales<BR>Ciudad Universitaria - Pab. 2 - Piso
3</FONT></DIV></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 6pt" align=center><SPAN lang=EN-US
style="FONT-SIZE: 14pt; FONT-FAMILY: Arial; mso-bidi-font-weight: bold; mso-bidi-font-size: 10.0pt"><STRONG>The
Nitrophorins from a <?xml:namespace prefix = st2 ns =
"urn:schemas-microsoft-com:office:smarttags" /><st2:place w:st="on">New
World</st2:place> Blood-Sucking Insect: NMR Spectra and Effects of Protein Side
Chains on the Redox Stability of the Fe-NO Complexes
<o:p></o:p></STRONG></SPAN></P>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 6pt" align=center><SPAN lang=EN-US
style="FONT-FAMILY: Arial"><STRONG><FONT size=3>F. Ann
Walker</FONT></STRONG></SPAN></P>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 6pt" align=center><SPAN lang=EN-US
style="FONT-FAMILY: Arial"><STRONG><FONT size=3>Department of Chemistry and
Biochemistry, The <st2:place w:st="on"><st2:PlaceType
w:st="on">University</st2:PlaceType> of <st2:PlaceName
w:st="on">Arizona</st2:PlaceName></st2:place>
<o:p></o:p></FONT></STRONG></SPAN></P>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 6pt" align=center><STRONG><FONT
size=3><st2:place w:st="on"><st2:City w:st="on"><SPAN lang=EN-US
style="FONT-FAMILY: Arial">Tucson</SPAN></st2:City><SPAN lang=EN-US
style="FONT-FAMILY: Arial">, <st2:State w:st="on">AZ</st2:State><SPAN
style="mso-spacerun: yes"> </SPAN><st2:PostalCode
w:st="on">85721-0041</st2:PostalCode></SPAN></st2:place></FONT></STRONG></P>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 6pt" align=justify><SPAN lang=EN-US
style="FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT size=3>The
nitrophorins (NP) from the salivary glands of the kissing bug (<I
style="mso-bidi-font-style: normal">Rhodnius prolixus</I>) have been cloned,
sequenced, expressed, purified and characterized by optical, EPR, NMR, FTIR and
resonance Raman spectroscopies, X-ray crystallography, and electrochemistry.
These are unique heme proteins which are stabilized in the Fe(III) oxidation
state, which thus insures that NO can dissociate from the proteins upon the
insect’s injection of them into the tissues of the victim. This injection
dilutes the NO-binding proteins by approximately 100-fold. There are at least
seven nitrophorins in the <I style="mso-bidi-font-style: normal">R. prolixus</I>
saliva that display interesting similarities and differences. All have molecular
weights of about 20 kD. In this seminar the NMR spectra of high- and low-spin
forms of the four nitrophorins of the adult insect will be discussed briefly to
illustrate the information that can be obtained from paramagnetic heme proteins.
In addition, the factors which stabilize the ferriheme-NO complexes over the
corresponding ferroheme-NO complexes, and the reasons why it is fortunate that
the proteins are stabilized in the Fe(III) state, will be
discussed.<o:p></o:p></FONT></SPAN></P>
<P class=MsoBodyText2 style="MARGIN: 0cm 0cm 6pt; TEXT-ALIGN: center"
align=center><SPAN lang=EN-US
style="FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT size=3>Background
information:<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 13.85pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Reversible Binding of
Nitric Oxide by a Salivary Nitrosylheme Protein from the Blood Sucking Insect,
<I style="mso-bidi-font-style: normal">Rhodnius prolixus</I>,” Ribeiro, J. M.
C.; Hazzard, J. M. H.; Nussenzveig, R.; Champagne, D.; Walker, F. A. <I
style="mso-bidi-font-style: normal">Science</I> <B
style="mso-bidi-font-weight: normal">1993</B>, <I
style="mso-bidi-font-style: normal">260</I>, 539-541.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 0cm 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Crystal Structures of a
Nitric Oxide Transport Protein from a Blood-Sucking Insect,” Weichsel, A.;
Andersen, J. F.; Champagne, D. E.; Walker, F. A.; Montfort, W. R. <I
style="mso-bidi-font-style: normal">Nature Struct. Biol.</I> <B
style="mso-bidi-font-weight: normal">1998</B>, <I
style="mso-bidi-font-style: normal">5</I>, 304-309.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 13.85pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Nitric Oxide Binding to
Nitrophorin 4 Induces Complete Distal Pocket Burial,” Weichsel, A.; Andersen, J.
F.; Roberts, S. A.; Montfort, W. R. <I
style="mso-bidi-font-style: normal">Nature Struct. Biol. </I><B
style="mso-bidi-font-weight: normal">2000</B><I
style="mso-bidi-font-style: normal">, 7</I>, 551-556.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Kinetics and Equilibria
in Ligand Binding by Nitrophorins 1-4:<SPAN style="mso-spacerun: yes">
</SPAN>Evidence for Stabilization of a NO-Ferriheme Complex through a
Ligand-Induced Conformational Trap,” Andersen, J. F.; Ding, X. D.; Balfour, C.;
Champagne, D. E.; Walker, F. A.; Montfort, W. R. <I
style="mso-bidi-font-style: normal">Biochemistry</I> <B
style="mso-bidi-font-weight: normal">2000</B>, <I
style="mso-bidi-font-style: normal">39</I>, 10118-10131.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Ligand-Induced Heme
Ruffling and Bent NO Geometry in Ultra-High Resolution Structures of Nitrophorin
4,” Roberts, S. A.; Weichsel, A.; Qin, Y.; Shelnutt, J. A.; <SPAN
style="mso-bidi-font-weight: bold">Walker, F. A.</SPAN>; Montfort, W. R.
<I>Biochemistry</I> <B>2001</B>, <I>40</I>, 11327-11337.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Electrochemical and NMR
Spectroscopic Studies of Distal Pocket Mutants of Nitrophorin 2:<SPAN
style="mso-spacerun: yes"> </SPAN>Stability, Structure and Dynamics of
Axial Ligand Complexes,” Shokhireva, T. Kh.; Berry, R. E.; Uno, E.; Balfour, C.
A.; Zhang, H.; Walker, F.<B> </B>A. <I style="mso-bidi-font-style: normal">Proc.
Natl. Acad. Sci. USA</I> <B>2003</B>, <I
style="mso-bidi-font-style: normal">100</I>, 3778-3783.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Nitric Oxide Interaction
with Insect Nitrophorins, and Thoughts on the Electron Configuration of the
<?xml:namespace prefix = st1 ns = "isiresearchsoft-com/cwyw" /><st1:citation
w:st="on">{FeNO}</st1:citation><SUP>6</SUP> Complex,” Walker, F. A. <I
style="mso-bidi-font-style: normal">J. Inorg. Biochem</I>. <B
style="mso-bidi-font-weight: normal">2005</B>, <I
style="mso-bidi-font-style: normal">99</I>, 216-236.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Effect of the N-Terminus
on Heme Cavity Structure, Ligand Equilibrium and Rate Constants, and Reduction
Potentials of Nitrophorin 2 from <I style="mso-bidi-font-style: normal">Rhodnius
prolixus</I>,” Berry, R. E.; Shokhireva, T. Kh.; Filippov, I.; Shokhirev, M. N.;
Zhang, H.; <SPAN style="mso-bidi-font-weight: bold">Walker, F. A.</SPAN> <I
style="mso-bidi-font-style: normal">Biochemistry</I> <B
style="mso-bidi-font-weight: normal">2007</B>, <I
style="mso-bidi-font-style: normal">46</I>, 6830-6843. <o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Assignment of the
Ferriheme Resonances for Low-Spin Complexes of Nitrophorins 1 and 4 by
<SUP>1</SUP>H and <SUP>13</SUP>C NMR Spectroscopy: Comparison to Structural Data
Obtained from X-Ray Crystallography,” Shokhireva, T. Kh.; Weichsel, A.; Smith,
K. M.; Berry, R. E.; Shokhirev, N. V.; Balfour, C.; Zhang, H.; Montfort, W. R.;
Walker, F. A. <I style="mso-bidi-font-style: normal">Inorg. Chem. </I><B
style="mso-bidi-font-weight: normal">2007</B>, <I
style="mso-bidi-font-style: normal">46</I>, 2041-2056.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“Assignment of Ferriheme
Resonances for High- and Low-Spin Forms of the Symmetrical Hemin-Reconsti-tuted
Nitrophorins 1-4 by <SUP>1</SUP>H and <SUP>13</SUP>C NMR Spectroscopy: The
Dynamics of Heme Ruffling Deformations,” Sho-khireva, T. K.; Shokhirev, N. V.;
Berry, R. E.; Zhang, H.; <SPAN style="mso-bidi-font-weight: bold">Walker, F.
A.</SPAN> <I>J. Biol. Inorg. Chem.</I> <B
style="mso-bidi-font-weight: normal">2008</B><I
style="mso-bidi-font-style: normal">,13</I>, 941-959.<o:p></o:p></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 3pt; tab-stops: -54.0pt -22.7pt -7.05pt 27.0pt 50.4pt 86.9pt 123.45pt 160.0pt 196.55pt 233.1pt 269.6pt 300.95pt 337.5pt 374.0pt 410.55pt 447.1pt 483.65pt"><SPAN
lang=EN-US style="FONT-SIZE: 11pt; FONT-FAMILY: Arial">“The Effect of Mutation
of Carboxylate Side-Chain Amino Acids Near the Heme on the Reduction Potentials
and Ligand Binding Constants of Nitrophorin 2 and its NO, Histamine and
Imidazole Complexes,” Berry, R. E.; Shokhirev, M. N.; Ho, A. Y. W.; Yang, F.;
Shokhireva, T. K.; Zhang, H.; Weichsel, A.; Montfort, W. R.; <SPAN
style="mso-bidi-font-weight: bold">Walker, F. A.</SPAN> <I
style="mso-bidi-font-style: normal">J. Am. Chem. Soc.</I> <B>2009</B>,
<I>131</I>, 2313-2327.<o:p></o:p></SPAN></P></FONT></DIV></BODY></HTML>