A Systematic Review of the Design and Applications of Antimicrobial Peptides in Wound Healing.

The sources of antimicrobial peptides (AMPs), also known as peptide-based antibiotics, are diverse, such as plants, animals, microorganisms including human leukocytes, saliva, human defense peptides, and human sweat. These natural sources provide a rich variety of AMPs with unique characteristics and potential therapeutic applications, including wound-healing and antimicrobial properties. AMPs derived from these sources have shown promise in combating a wide range of pathogens, making them valuable targets for further research and potential clinical applications. The design of AMPs for wound healing involves a meticulous process of structurally optimizing peptides to possess a unique combination of antibacterial and wound-healing characteristics. This systematic review was produced to show the design and applications of AMPs in wound healing. The terms "antimicrobial peptides AND wound healing" were used to search for articles published between September 2023 and January 2010. In the search, we found a total of 12958 articles, of which 12898 were excluded, and the remaining 60 articles were chosen for further study. This systematic review underscores the potential of AMPs as valuable tools in infection control and wound healing, showcasing their versatility and effectiveness in combating a wide range of pathogens. Overall, AMPs in wound healing display a diverse mechanism of action, influencing the inflammatory response, encouraging tissue regeneration, and aiding tissue remodeling, along with strong antibacterial activity. Furthermore, this systematic review addresses AMP toxicity studies, which include rigorous in vitro and in vivo examinations to determine potential cytotoxic effects, systemic toxicity, and any adverse responses connected with its usage in wound-healing applications.

Proteomic analysis of near-isogenic lines reveals key biomarkers on wheat chromosome 4B conferring drought tolerance.

Drought is a major constraint for wheat production that is receiving increased attention due to global climate change. This study conducted isobaric tags for relative and absolute quantitation proteomic analysis on near-isogenic lines to shed light on the underlying mechanism of qDSI.4B.1 quantitative trait loci (QTL) on the short arm of chromosome 4B conferring drought tolerance in wheat. Comparing tolerant with susceptible isolines, 41 differentially expressed proteins were identified to be responsible for drought tolerance with a p-value of < 0.05 and fold change >1.3 or <0.7. These proteins were mainly enriched in hydrogen peroxide metabolic activity, reactive oxygen species metabolic activity, photosynthetic activity, intracellular protein transport, cellular macromolecule localization, and response to oxidative stress. Prediction of protein interactions and pathways analysis revealed the interaction between transcription, translation, protein export, photosynthesis, and carbohydrate metabolism as the most important pathways responsible for drought tolerance. The five proteins, including 30S ribosomal protein S15, SRP54 domain-containing protein, auxin-repressed protein, serine hydroxymethyltransferase, and an uncharacterized protein with encoding genes on 4BS, were suggested as candidate proteins responsible for drought tolerance in qDSI.4B.1 QTL. The gene coding SRP54 protein was also one of the differentially expressed genes in our previous transcriptomic study.

Interaction of ferritin iron responsive element (IRE) mRNA with translation initiation factor eIF4F.

The interaction of ferritin iron responsive element (IRE) mRNA with eIF4F was examined by fluorescence and circular dichroism spectroscopy. Fluorescence quenching data indicated that eIF4F contains one high affinity binding site for ferritin IRE RNA. The Scatchard analysis revealed strong binding affinity (Ka = 11.1 × 107 M-1) and binding capacity (n = 1.0) between IRE RNA and eIF4F. The binding affinity of IRE RNA for eIF4F decreased (~4-fold) as temperature increased (from 5 °C to 30 °C). The van't Hoff analysis revealed that IRE RNA binding to eIF4F is enthalpy-driven (ΔH = -47.1 ± 3.4 kJ/mol) and entropy-opposed (ΔS = -30.1 ± 1.5 J/mol/K). The addition of iron increased the enthalpic, while decreasing the entropic contribution towards the eIF4F•IRE RNA complex, resulting in favorable free energy (ΔG = -49.8 ± 2.8 kJ/mol). Thermodynamic values and ionic strength data suggest that the presence of iron increases hydrogen bonding and decreases hydrophobic interactions, leading to formation of a more stable complex. The interaction of IRE RNA with eIF4F at higher concentrations produced significant changes in the secondary structure of the protein, as revealed from the far-UV CD results, clearly illustrating the structural alterations resulted from formation of the eIF4F•IRE RNA complex. A Lineweaver-Burk plot showed an uncompetitive binding behavior between IRE RNA and m7G cap for the eIF4F, indicating that there are different binding sites on the eIF4F for the IRE RNA and the cap analog; molecular docking analysis further supports this notion. Our findings suggest that the eIF4F•IRE RNA complex formation is accompanied by an elevated hydrogen bonding and weakened hydrophobic interactions, leading to an overall conformational change, favored in terms of its free energy. The conformational change in the eIF4F structure, caused by the IRE RNA binding, provides a more stable platform for effective IRE translation in iron homeostasis.

Proteomic profiling of developing wheat heads under water-stress.

A replicated iTRAQ (isobaric tags for relative and absolute quantification) study on developing wheat heads from two doubled haploid (DH) lines identified from a cross between cv Westonia x cv Kauz characterized the proteome changes influenced by reproductive stage water-stress. All lines were exposed to 10 days of water-stress from early booting (Zadok 40), with sample sets taken from five head developmental stages. Two sample groups (water-stressed and control) account for 120 samples that required 18 eight-plex iTRAQ runs. Based on the IWGSC RefSeq v1 wheat assembly, among the 4592 identified proteins, a total of 132 proteins showed a significant response to water-stress, including the down-regulation of a mitochondrial Rho GTPase, a regulator of intercellular fundamental biological processes (7.5 fold) and cell division protein FtsZ at anthesis (6.0 fold). Up-regulated proteins included inosine-5'-monophosphate dehydrogenase (3.83 fold) and glycerophosphodiester phosphodiesterase (4.05 fold). The Pre-FHE and FHE stages (full head emerged) of head development were differentiated by 391 proteins and 270 proteins differentiated the FHE and Post-FHE stages. Water-stress during meiosis affected seed setting with 27% and 6% reduction in the progeny DH105 and DH299 respectively. Among the 77 proteins that differentiated between the two DH lines, 7 proteins were significantly influenced by water-stress and correlated with the seed set phenotype response of the DH lines to water-stress (e.g. the up-regulation of a subtilisin-like protease in DH 299 relative to DH 105). This study provided unique insights into the biological changes in developing wheat head that occur during water-stress.

Monomeric Camelus dromedarius GSTM1 at low pH is structurally more thermostable than its native dimeric form.

Glutathione S‒transferases (GSTs) are multifunctional enzymes that play an important role in detoxification, cellular signalling, and the stress response. Camelus dromedarius is well-adapted to survive in extreme desert climate and it has GSTs, for which limited information is available. This study investigated the structure-function and thermodynamic properties of a mu-class camel GST (CdGSTM1) at different pH. Recombinant CdGSTM1 (25.7 kDa) was expressed in E. coli and purified to homogeneity. Dimeric CdGSTM1 dissociated into stable but inactive monomeric subunits at low pH. Conformational and thermodynamic changes during the thermal unfolding pathway of dimeric and monomeric CdGSTM1 were characterised via a thermal shift assay and dynamic multimode spectroscopy (DMS). The thermal shift assay based on intrinsic tryptophan fluorescence revealed that CdGSTM1 underwent a two-state unfolding pathway at pH 1.0-10.0. Its Tm value varied with varying pH. Another orthogonal technique based on far-UV CD also exhibited two-state unfolding in the dimeric and monomeric states. Generally, proteins tend to lose structural integrity and stability at low pH; however, monomeric CdGSTM1 at pH 2.0 was thermally more stable and unfolded with lower van't Hoff enthalpy. The present findings provide essential information regarding the structural, functional, and thermodynamic properties of CdGSTM1 at pH 1.0-10.0.

Analysis of Reproducibility of Proteome Coverage and Quantitation Using Isobaric Mass Tags (iTRAQ and TMT).

This study aimed to compare the depth and reproducibility of total proteome and differentially expressed protein coverage in technical duplicates and triplicates using iTRAQ 4-plex, iTRAQ 8-plex, and TMT 6-plex reagents. The analysis was undertaken because comprehensive comparisons of isobaric mass tag reproducibility have not been widely reported in the literature. The highest number of proteins was identified with 4-plex, followed by 8-plex and then 6-plex reagents. Quantitative analyses revealed that more differentially expressed proteins were identified with 4-plex reagents than 8-plex reagents and 6-plex reagents. Replicate reproducibility was determined to be ≥69% for technical duplicates and ≥57% for technical triplicates. The results indicate that running an 8-plex or 6-plex experiment instead of a 4-plex experiment resulted in 26 or 39% fewer protein identifications, respectively. When 4-plex spectra were searched with three software tools-ProteinPilot, Mascot, and Proteome Discoverer-the highest number of protein identifications were obtained with Mascot. The analysis of negative controls demonstrated the importance of running experiments as replicates. Overall, this study demonstrates the advantages of using iTRAQ 4-plex reagents over iTRAQ 8-plex and TMT 6-plex reagents, provides estimates of technical duplicate and triplicate reproducibility, and emphasizes the value of running replicate samples.

The Achilles' Heel of "Ultrastable" Hyperthermophile Proteins: Submillimolar Concentrations of SDS Stimulate Rapid Conformational Change, Aggregation, and Amyloid Formation in Proteins Carrying Overall Positive Charge.

Low concentrations (<3.0 mM) of the anionic surfactant sodium dodecyl sulfate (SDS) have been shown to induce the formation of amyloid fibers in more than 20 different mesophile-derived proteins in the cationic state. It is not known whether SDS has similar effects on hyperthermophile-derived proteins, which are otherwise thought to be "ultrastable" and inordinately resistant to structural perturbations at room temperature. Here, we show that low (<4.5 mM) concentrations of SDS rapidly induce the formation of aggregates and amyloid fibers in five different ultrastable Pyrococcus furiosus proteins in the cationic state. We also show that amyloid formation is accompanied by the development of a characteristic, negative circular dichroism band at ∼230 nm. These effects are not seen if the proteins have a net negative charge or when higher concentrations of SDS are used (which induce helix formation instead). Our results appear to reveal a potential weakness or "Achilles' heel" in ultrastable proteins from hyperthermophiles. They also provide very strong support for the view that SDS initially interacts with proteins through electrostatic interactions, and not hydrophobic interactions, eliciting similar effects entirely regardless of protein molecular weight, or structural features such as quaternary structure or tertiary structural stability.

Comparative insight into surfactants mediated amyloidogenesis of lysozyme.

Electrostatic and hydrophobic interactions have an important role in the protein aggregation. In this study, we have investigated the effect of charge and hydrophobicity of oppositely charged surfactants i.e., anionic (AOT and SDS) and cationic (CTAB and DTAB) on hen egg white lysozyme at pH 9.0 and 13.0, respectively. We have employed various methods such as turbidity measurements, Rayleigh light scattering, ThT, Congo red and ANS dye binding assays, far-UV CD, atomic force microscopy, transmission electron and fluorescence microscopy. At lower molar ratio, both anionic and cationic surfactants promote amyloid fibril formation in lysozyme at pH 9.0 and 13.0, respectively. The aggregation was proportionally increased with respect to protein concentration and hydrophobicity of surfactant. The morphology of aggregates at both the pH was fibrillar in structure, as visualized by dye binding and microscopic imaging techniques. Initially, the interaction between surfactants and lysozyme was electrostatic and then hydrophobic as investigated by ITC. This study demonstrates the crucial role of charge and hydrophobicity during amyloid fibril formation.

Protonation favors aggregation of lysozyme with SDS.

Different proteins have different amino acid sequences as well as conformations, and therefore different propensities to aggregate. Electrostatic interactions have an important role in the aggregation of proteins as revealed by our previous report (J. M. Khan et al., PLoS One, 2012, 7, e29694). In this study, we designed and executed experiments to gain knowledge of the role of charge variations on proteins during the events of protein aggregation with lysozyme as a model protein. To impart positive and negative charges to proteins, we incubated lysozyme at different pH values of below and above the pI (∼11). Negatively charged SDS was used to 'antagonize' positive charges on lysozyme. We examined the effects of pH variations on SDS-induced amyloid fibril formation by lysozyme using methods such as far-UV circular dichroism, Rayleigh scattering, turbidity measurements, dye binding assays and dynamic light scattering. We found that sub-micellar concentrations of SDS (0.1 to 0.6 mM) induced amyloid fibril formation by lysozyme in the pH range of 10.0-1.0 and maximum aggregation was observed at pH 1.0. The morphology of aggregates was fibrillar in structure, as visualized by transmission electron microscopy. Isothermal titration calorimetry studies demonstrated that fibril formation is exothermic. To the best of our current understanding of the mechanism of aggregation, this study demonstrates the crucial role of electrostatic interactions during amyloid fibril formation. The model proposed here will help in designing molecules that can prevent or reverse the amyloid fibril formation or the aggregation.

Hydrophobicity alone can not trigger aggregation in protonated mammalian serum albumins.

Amyloid fibrils are associated with neurodegenerative disorders and are formed by a number of proteins. In this study, the amyloid-forming behavior of several different serum albumins was examined at pH 3.5 i.e., about two pH units below their isoelectric points (pI ∼ 5.5) to examine the roles played by negative charge and hydrophobicity of exogenously added surfactants such as SDS, SDBS and AOT. The propensities of SDS, SDBS and AOT to promote the formation of amyloid fibrils were investigated by using measurements of turbidity, Rayleigh scattering, ThT and CR dye binding, DLS as well as far-UV CD. At submicellar concentrations of SDS and SDBS (0.5-2.5 mM) amyloid fibrils were formed by all albumins studied whereas at higher concentrations amyloid fibril formation was completely inhibited. Interestingly AOT promoted amyloid fibril formation up to 11 mM without any inhibition. The interaction between the albumins and the surfactants was exothermic, as confirmed by isothermal titration calorimetry (ITC). From the turbidity, Rayleigh scattering and dynamic light scattering data, it was concluded that amyloid induction was promoted most by AOT followed by SDBS and SDS. Similar studies were performed at pH 7.4 i.e., about two units of pH above the albumins pI, and no amyloid fibrils were formed. From these studies we conclude that negatively charged surfactants induce amyloid fibril formation in serum albumins with the help of electrostatic and hydrophobic interactions. Besides the study performed at pH 7.4 indicates that hydrophobic interactions alone can not induce aggregation in serum albumins.

Molten globule of hemoglobin proceeds into aggregates and advanced glycated end products.

Conformational alterations of bovine hemoglobin (Hb) upon sequential addition of glyoxal over a range of 0-90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG) state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD) and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased ß-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT) fluorescence and red shifted Congo Red (CR) absorbance. On incubating Hb with 30% v/v glyoxal for 0-20 days, advanced glycation end products (AGEs) were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular ß-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to ß-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington's.

Monomeric banana lectin at acidic pH overrules conformational stability of its native dimeric form.

Banana lectin (BL) is a homodimeric protein categorized among jacalin-related family of lectins. The effect of acidic pH was examined on conformational stability of BL by using circular dichroism, intrinsic fluorescence, 1-anilino-8-napthalene sulfonate (ANS) binding, size exclusion chromatography (SEC) and dynamic light scattering (DLS). During acid denaturation of BL, the monomerization of native dimeric protein was found at pH 2.0. The elution profile from SEC showed two different peaks (59.65 ml & 87.98 ml) at pH 2.0 while single peak (61.45 ml) at pH 7.4. The hydrodynamic radii (R h) of native BL was 2.9 nm while at pH 2.0 two species were found with R h of 1.7 and 3.7 nm. Furthermore at, pH 2.0 the secondary structures of BL remained unaltered while tertiary structure was significantly disrupted with the exposure of hydrophobic clusters confirming the existence of molten globule like state. The unfolding of BL with different subunit status was further evaluated by urea and temperature mediated denaturation to check their stability. As inferred from high Cm and ΔG values, the monomeric form of BL offers more resistance towards chemical denaturation than the native dimeric form. Besides, dimeric BL exhibited a Tm of 77°C while no loss in secondary structures was observed in monomers even up to 95°C. To the best of our knowledge, this is the first report on monomeric subunit of lectins showing more stability against denaturants than its native dimeric state.

Functional annotation of the human chromosome 7 "missing" proteins: a bioinformatics approach.

The chromosome-centric human proteome project aims to systematically map all human proteins, chromosome by chromosome, in a gene-centric manner through dedicated efforts from national and international teams. This mapping will lead to a knowledge-based resource defining the full set of proteins encoded in each chromosome and laying the foundation for the development of a standardized approach to analyze the massive proteomic data sets currently being generated. The neXtProt database lists 946 proteins as the human proteome of chromosome 7. However, 170 (18%) proteins of human chromosome 7 have no evidence at the proteomic, antibody, or structural levels and are considered "missing" in this study as they lack experimental support. We have developed a protocol for the functional annotation of these "missing" proteins by integrating several bioinformatics analysis and annotation tools, sequential BLAST homology searches, protein domain/motif and gene ontology (GO) mapping, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Using the BLAST search strategy, homologues for reviewed non-human mammalian proteins with protein evidence were identified for 90 "missing" proteins while another 38 had reviewed non-human mammalian homologues. Putative functional annotations were assigned to 27 of the remaining 43 novel proteins. Proteotypic peptides have been computationally generated to facilitate rapid identification of these proteins. Four of the "missing" chromosome 7 proteins have been substantiated by the ENCODE proteogenomic peptide data.

1-Anilino-8-naphthalene sulfonate (ANS) is not a desirable probe for determining the molten globule state of chymopapain.

The molten globule (MG) state of proteins is widely detected through binding with 1-anilino-8-naphthalene sulphonate (ANS), a fluorescent dye. This strategy is based upon the assumption that when in molten globule state, the exposed hydrophobic clusters of protein are readily bound by the nonpolar anilino-naphthalene moiety of ANS molecules which then produce brilliant fluorescence. In this work, we explored the acid-induced unfolding pathway of chymopapain, a cysteine proteases from Carica papaya, by monitoring the conformational changes over a pH range 1.0-7.4 by circular dichroism, intrinsic fluorescence, ANS binding, acrylamide quenching, isothermal titration calorimetry (ITC) and dynamic light scattering (DLS). The spectroscopic measurements showed that although maximum ANS fluorescence intensity was observed at pH 1.0, however protein exhibited ∼80% loss of secondary structure which does not comply with the characteristics of a typical MG-state. In contrast at pH 1.5, chymopapain retains substantial amount of secondary structure, disrupted side chain interactions, increased hydrodynamic radii and nearly 30-fold increase in ANS fluorescence with respect to the native state, indicating that MG-state exists at pH 1.5 and not at pH 1.0. ITC measurements revealed that ANS molecules bound to chymopapain via hydrophobic interaction were more at pH 1.5 than at pH 1.0. However, a large number of ANS molecules were also involved in electrostatic interaction with protein at pH 1.0 which, together with hydrophobically interacted molecules, may be responsible for maximum ANS fluorescence. We conclude that maximum ANS-fluorescence alone may not be the criteria for determining the MG of chymopapain. Hence a comprehensive structural analysis of the intermediate is essentially required.

Graphene quilts for thermal management of high-power GaN transistors.

Self-heating is a severe problem for high-power gallium nitride (GaN) electronic and optoelectronic devices. Various thermal management solutions, for example, flip-chip bonding or composite substrates, have been attempted. However, temperature rise due to dissipated heat still limits applications of the nitride-based technology. Here we show that thermal management of GaN transistors can be substantially improved via introduction of alternative heat-escaping channels implemented with few-layer graphene-an excellent heat conductor. The graphene-graphite quilts were formed on top of AlGaN/GaN transistors on SiC substrates. Using micro-Raman spectroscopy for in situ monitoring we demonstrated that temperature of the hotspots can be lowered by ∼20 °C in transistors operating at ∼13 W mm(-1), which corresponds to an order-of-magnitude increase in the device lifetime. The simulations indicate that graphene quilts perform even better in GaN devices on sapphire substrates. The proposed local heat spreading with materials that preserve their thermal properties at nanometre scale represents a transformative change in thermal management.

Complexation behavior of gelatin with amphiphilic drug imipramine hydrochloride as studied by conductimetry, surface tensiometry and circular dichroism studies.

Herein we report our studies carried out on the interaction between IMP and gelatin in aqueous medium at 25°C using conductimetry, surface tensiometry and circular dichroism (CD) techniques. Both surface tensiometry and conductimetry results indicate that the drug interacts with the gelatin in a surfactant-like manner, i.e., both critical aggregation (cac) and polymer saturation points (psp) were observed. The interaction starts with the formation of a highly surface-active complex as revealed by the lowering of surface tension on the addition of drug to the macromolecule. The decrease in cac on increasing gelatin concentration is an indication of the strong interaction between gelatin and IMP. However, at low concentration of gelatin the interaction was not much strong as exposed by surface tension study, i.e., the cac was not very clear (as with higher gelatin concentrations). As usual, the psp increased on increasing the gelatin concentration and was always higher than the critical micelle concentration of the drug in pure aqueous medium. Using CD measurements the influence of IMP on the secondary structure of gelatin in aqueous solutions was also investigated. CD studies (performed at very low drug concentrations) illustrated that the random coil content of gelatin increases with increasing drug concentration. Free energies of aggregation (ΔG(agg)) and micellization (ΔG(mic)) were computed with the help of degrees of micelle ionization obtained from the specific conductivity - [IMP] plots.

Unfolding of rabbit serum albumin by cationic surfactants: surface tensiometry, small-angle neutron scattering, intrinsic fluorescence, resonance Rayleigh scattering and circular dichroism studies.

Unfolding of rabbit serum albumin (RSA) by cationic surfactants cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) was studied by exploiting surface tensiometry, small-angle neutron scattering (SANS), intrinsic fluorescence, resonance Rayleigh scattering (RRS) (also referred as turbidity at 350/350), and circular dichroism (CD) techniques. Surface tension measurements revealed the formation of highly surface-active complexes occurring as a consequence of RSA-surfactants interactions. SANS measurements show that, in the low surfactant concentration regime (0-10 mM), increase in the dimension of the ellipsoidal protein occurs. Conversely, at higher concentrations (20-80 mM), the surfactant molecules result in the formation of a fractal structure representing a 'necklace model' of micelle-like clusters randomly distributed along the polypeptide chain. The overall size of the complex increases and the fractal dimension decreases on increasing the surfactant concentration. The size of the micelle-like clusters decreases while the number of such clusters and their aggregation number increase with increasing CTAB concentration. Taken all observant together, the fluorescence, RRS, and CD studies were found to be consistent with the SANS measurements. Both CTAB and TTAB were found to behave likewise and the effect of hydrophobicity was clearly visible in the CD, RRS, and intrinsic fluorescence results. The Rayleigh scattering study shows that TTAB was more skilled to solubilize the serum albumin and may be more convenient than CTAB to isolate proteins from inclusion bodies.

Multi-technique approach on the effect of surfactant concentrations on the thermal unfolding of rabbit serum albumin: formation and solubilization of the protein aggregates.

Effect of cationic surfactant, cetyltrimethylammonium bromide (CTAB) addition on the thermal denaturation of rabbit serum albumin (RSA) has been studied by employing small-angle neutron scattering (SANS), circular dichroism (CD), intrinsic fluorescence and ultra violet (UV) spectroscopy. The studies were performed at three different temperatures viz., 30, 50 and 70 degrees C and at two different concentrations of CTAB: the low concentration of CTAB used was 1mM and the higher concentration was 80 mM (for SANS) and 20mM (for CD, fluorescence and UV). A collective effect of high temperature and low concentration of CTAB led to the protein aggregation followed by solubilization of these aggregates at higher concentration of surfactant. At 1mM CTAB and 30 degrees C, the protein-surfactant complex has a prolate ellipsoidal shape with semi-major axis of 88.9A and semi-minor axis of 19.6A which are slightly greater than the values of the native RSA. At 50 degrees C, the size of the semi-major axis increases while at 70 degrees C an increase in the size of both axes was found. The thermal outcome at higher concentration of CTAB (80 mM) was rather different. Higher concentration of CTAB unfolds the protein by the formation of micelle-like aggregates along the polypeptide chains of the protein and the complex was stabilized at higher temperatures, which was not found with lower concentration of CTAB. The CD results were found to be consistent with the SANS results, i.e., decrease in alpha-helicity of RSA was more when less amount of surfactant was present as compared to the system with higher surfactant concentration. In a similar fashion, results of relative fluorescence intensity (RFI) reveal that increase in temperature causes decrease in lambda(max) of native RSA as well as RSA+1mM CTAB, whereas the lambda(max) remains unchanged for RSA+20mM CTAB systems. That means the structure remains compact in presence of 20mM CTAB while the structure becomes loose when low or zero amount of surfactant was present. The UV results indicate that the protein aggregation takes place in presence of low amount of CTAB and these aggregates become soluble at high concentration of CTAB.