The Crystal Structure of Met-Rantes: Comparison with Native Rantes and Aop-Rantes. Pp. 73-82.
David M. Hoover , Jeffrey Shaw ,
Zygmunt Gryczynski, Amanda E.I. Proudfoot , Tim Wells, and Jacek Lubkowski
[Abstract]
A Comparative Study of the Function of Phospholipases A2 From Agkistrodon Acutus. Pp. 83-90.
Xiaolong Liu, Ying Xiong, Xiangfu Wu, Yuancong
Zhou *
[Abstract]
Occurrence of An Essential Amino Acid Residues in the Lytic Effect of Escherichia Coli a -Haemolysin. Pp. 91-98.
Laura Bakas*
[Abstract]
Analysis of the Membrane Interactive Potential of the Escherichia Coli PBP6B C-Terminus Pp. 99-104.
David A. Phoenix* and James Wallace
[Abstract]
Protein Photodegradatin in the Fluorescence Unfolding Kinetics Study of Bromelain. Pp. 105-112.
Alfonso Arroyo-Reyna* and Salvador R. Tello-Solis
[Abstract]
Ab Initio Study of The Lim-Akh-I Peptide in Gas-Phase Environment. Pp. 113-11.
Igor Z. Zubrzycki
[Abstract]
Effect of Chiral Guest Residue on the Conformation of Short Peptide Containing The Gly-Dpg/Gly Segment: A Cd Investigation. Pp. 117-122.
Kalpana Bhargava* and R. Balaji Roa
[Abstract]
Divergences in Homeodomains of Hox Genes and Von Baer’s Law. Pp. 123-131.
Rong-Qiao He* and Jun-Lan Yao
[Abstract]
Conformational Changes of Human Neuronal Tau During Thermal and Guanidine-Hcl Denaturation. Pp. 133-141.
Jian-Ying Luo, Yang Liu, Qian Hua and Rong-Qiao He
[Abstract]
[Back to top] The Crystal Structure of Met-Rantes: Comparison with Native Rantes and Aop-Rantes.
David M. Hoover , Jeffrey Shaw , Zygmunt Gryczynski, Amanda E.I. Proudfoot , Tim Wells, and Jacek Lubkowski.
Met-RANTES is a modified version of the chemokine RANTES, which has an additional amino acid at the amino terminus. To compare Met-RANTES with the native protein as well as with another antagonist, AOP-RANTES, we have solved the structure of Met-RENTES at 1.6 Å by X-ray crystallography and investigated the dimerization of all three proteins by fluorescence anisotropy. The dimerization of AOP-RANTES shows an altered aggregation profile. The delineation of slight differences in binding sulfate anions by Met-and AOP-RANTES might be linked to specific yet different interactions between these proteins and glycosaminologycans.
[Back to top] A Comparative Study of the Function of Phospholipases A2 From Agkistrodon Acutus.
Xiaolong Liu, Ying Xiong, Xiangfu Wu, Yuancong Zhou *
cDNAs encoding acidic phospholipases A2I and acid2II, basic phospholipase A2 and Lys49-phospholipase A2 from Agkistrodon acutus were inserted into bacterial expression vectors and effectively expressed in E.coli RR1. Except for Lys49-phospholipase A2, the other phospholipase A2s have high enzymatic activities. Acidic phospholipase A2I has an inhibiting effect on platelet aggregation. All phospholipase A2s except acidic phospholipase A2II have hemolytic activities. The roles of various amino acid residues in the enzymatic, hemolytic and platelet aggregation inhibiting activities of phospholipase A2 are discussed.
[Back to top] Occurrence of An Essential Amino Acid Residues in the Lytic Effect of Escherichia Coli a -Haemolysin.
Laura Bakas*
a-Hemolysin (HlyA), an extracellular protein toxin
produced by some pathogenic strains of Escherichia coli, is known to disrupt
eukaryotic cell membranes. In an attempt to correlate the structure of the
toxin with its function, we studied the role of the histidine residues on the
toxin activity by their chemical modification with the reagent diethly1
pyrocarbonate (DEPC). The results of this study suggest the presence of an
essential histidine residue at the Ca2+-binding motif and its role
in the lytic action of E.coli HiyA.
[Back to top] Analysis of the Membrane Interactive Potential of the Escherichia Coli PBP6B C-Terminus.
David A. Phoenix* and James Wallace
Escherichia coli low molecular weight penicillin binding proteins include PBP4,5,6, and recently PBP6b, PBP5 and PBP6 have been shown to possess C-terminal amphiphilic helical anchors. PBP4 has been shown to have the potential to interact at the membrane interface but the proteins appear to bind via a different mechanism to PBP5, and PBP6. It has been suggested that since PBP6b has a high homology with PBP6 it also binds via an amphiphilic alpha helix. Here helical wheel, hydrophobic moment and DWIH analysis are used to show that the C-terminus of PBP6b does not resemble the anchor regions of the PBP5 and 6 but may stabilize membrane binding using a mechanism similar to that of PBP4.
[Back to top] Protein
Photodegradatin in the Fluorescence Unfolding Kinetics Study of Bromelain.
Alfonso Arroyo-Reyna* and Salvador R. Tello-Solis
We have detected protein photodegradation in the fluorescence unfolding kinetics experiment of stem bromelain, a cysteine proteinase from the papain family. Thermally induced unfolding has been followed by near and far circular dichroism and tryptophan fluorescence emission. It was found that the fluorescence kinetics involves two phases. This biphasic nature results from ultraviolet induced photolysis of tryptophan.
[Back to top] Ab Initio Study of The Lim-Akh-I Peptide in Gas-Phase Environment.
Igor Z. Zubrzycki
Ab initio calculation (Hartree-Fock) using the minimal (STO-3G) basis set were performed on Lom-AKH-I peptide, an insect neuropeptide belonging to the large adipokinetic hormones/red pigment concentration hormones family (AKH/RPCH). The geometry optimized structure, energies and distribution of electrostatic charges were derived.
[Back to top] Effect of Chiral Guest Residue on the Conformation of Short Peptide Containing The Gly-Dpg/Gly Segment: A Cd Investigation.
Kalpana Bhargava* and R. Balaji Roa.
The Gly-Dpg-Gly segment (Drug =a, a-Dipropylglycine) has already been shown to adopt a fully extended conformation in solution as well as in solid state. In this paper we investigate the effect of chiral residues and the terminal aromatic groups on extended conformation in solution with a Gly-Dpg-Gly backbone, CD studies on these peptides indicate that a chiral L-Leu residue at the C-terminus leads to a type I’ /II’ b-turn. In addition we demonstrate the role of aromatic residues in the enhancement of CD intensities in the far UV region.
[Back to top] Divergences in Homeodomains of Hox Genes and Von Baer’s Law.
Rong-Qiao He* and Jun-Lan Yao
Divergences among homeodomains coded by Hox clusters of human beings have been analyzed with both methods of dynamic programming [1] and hydropathic mass [2]. Homeodomains of the interior genes (Hox A-1 to –4), including the paralogs of Hox B and Hox D, showed more distinguishable divergences than those of the posterior genes (from Hox A-5 to –13). The homeodomains grew exponentially more divergent in progression group 1 to 13 along a Hox complex. The divergence of homeodomains of Hox B-1 between C. elegans and human was small, but it became larger between those of the posterior genes. It appears that Hox genes should be involved in Von Baer’s law
[Back to top] Conformational Changes of Human Neuronal Tau During Thermal and Guanidine-Hcl Denaturation.
Jian-Ying Luo, Yang Liu, Qian Hua and Rong-Qiao He.
Unfolding of human neuronal tau was studied during incubation with guanidine hydrochloride (GuHCI) and under thermal denaturation conditions. The intensity of the intrinsic fluorescence at 305 nm increased markedly in GuHCI solutions. Fluorescence quenching by potassium iodide showed that Tyr residues approached to the interior of the molecule during GuHCI denaturation. The difference ultraviolet absorbance at 215 nm showed a marked increase above 45oC. Light scattering of tau solution intensity decreased when temperature increased. Kinetics of the increase in the absorbance was a biphasic procedure. The first order rate of the fast phase was 1.84 x10-1s-1 and that of the slow phase was 2.68 x10-2s-1. The difference absorbance of tau was reversible. Kinetics of a decrease in the difference absorbance was a fast procedure during tau refolding. The first order of the fast phase was much greater than that of the unfolding procedure. This suggests that tau is not completely at a random conformation at room temperature.