Functional and conformational characterization of new mutants of heart fatty acid-binding protein.
Ontology highlight
ABSTRACT:
SUBMITTER: Zimmerman AW
PROVIDER: S-EPMC1220668 | biostudies-other | 1999 Dec
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Human muscle fatty acid-binding protein (M-FABP) is a 15 kDa cytosolic protein which may be involved in fatty acid transfer and modulation of non-esterified fatty acid concentration in heart, skeletal muscle, kidney and many other tissues. Crystallographic studies have suggested the importance of the amino acids Thr-40, Arg-106, Arg-126 and Tyr-128 for the hydrogen bonding network of the fatty acid carboxylate group. Two phenylalanines at 16 and 57 are positioned to interact with the acyl chain of the fatty acid. We prepared 13 mutant proteins by site-directed mutagenesis and tested them for fatty acid binding and stability. Substitution of amino acids Phe-16, Arg-106 or Arg-126 created proteins which showed a large decrease in or complete loss of oleic acid binding. Substitution of Phe-57 by Ser or Val and of Tyr-128 by Phe had no great effect. The stability of the mutant proteins was tested by denaturation studies on the basis of fatty acid binding or tryptophan fluorescence and compared with that of the wild-type M-FABP. There was no direct relationship between fatty acid-binding activity and stability. Less stable mutants (F57S and Y128F) did not show a marked change in fatty acid-binding activity. Substitution of Arg-126 by Gln or Arg-106 by Thr eliminated binding activity, but the former mutant protein showed wild-type stability, in contrast to the latter. The results are in agreement with crystallographic data.
| S-EPMC1217033 | biostudies-other
Project description:BackgroundEpidemiological and molecular findings suggest a relationship between Alzheimer's disease (AD) and dyslipidemia, although the nature of this association is not well understood.ResultsUsing linear mixed effects models, we investigated the relationship between CSF levels of heart fatty acid binding protein (HFABP), a lipid binding protein involved with fatty acid metabolism and lipid transport, amyloid-? (A?), phospho-tau, and longitudinal MRI-based measures of brain atrophy among 295 non-demented and demented older individuals. Across all participants, we found a significant association of CSF HFABP with longitudinal atrophy of the entorhinal cortex and other AD-vulnerable neuroanatomic regions. However, we found that the relationship between CSF HABP and brain atrophy was significant only among those with low CSF A?1-42 and occurred irrespective of phospho-tau181p status.ConclusionsOur findings indicate that A?-associated volume loss occurs in the presence of elevated HFABP irrespective of phospho-tau. This implicates a potentially important role for fatty acid binding proteins in Alzheimer's disease neurodegeneration.
| S-EPMC3850652 | biostudies-literature
Project description:The complete amino acid sequence of a fatty acid-binding protein from human heart was determined by automated Edman degradation of CNBr, BNPS-skatole [3'-bromo-3-methyl-2-(2-nitrobenzenesulphenyl)indolenine], hydroxylamine, Staphylococcus aureus V8 proteinase, tryptic and chymotryptic peptides, and by digestion of the protein with carboxypeptidase A. The sequence of the blocked N-terminal tryptic peptide from citraconylated protein was determined by collisionally induced decomposition mass spectrometry. The protein contains 132 amino acid residues, is enriched with respect to threonine and lysine, lacks cysteine, has an acetylated valine residue at the N-terminus, and has an Mr of 14768 and an isoelectric point of 5.25. This protein contains two short internal repeated sequences from residues 48-54 and from residues 114-119 located within regions of predicted beta-structure and decreasing hydrophobicity. These short repeats are contained within two longer repeated regions from residues 48-60 and residues 114-125, which display 62% sequence similarity. These regions could accommodate the charged and uncharged moieties of long-chain fatty acids and may represent fatty acid-binding domains consistent with the finding that human heart fatty acid-binding protein binds 2 mol of oleate or palmitate/mol of protein. Detailed evidence for the amino acid sequences of the peptides has been deposited as Supplementary Publication SUP 50143 (23 pages) at the British Library Lending Division, Boston Spa, Yorkshire LS23 7BQ, U.K., from whom copies may be obtained as indicated in Biochem. J. (1988) 249, 5.
| S-EPMC1149123 | biostudies-other
Project description:Rat liver fatty-acid-binding protein (FABP) does not contain tryptophan. Three mutant proteins have been produced in which a single tryptophan residue has been inserted by site-directed mutagenesis at positions 3 (F3W), 18 (F18W) and 69 (C69W). These tryptophans have been strategically located in order to provide fluorescent reporter groups to study the binding and structural characteristics of rat liver FABP. Two fluorescent fatty acid analogues, DAUDA (11-[(5-dimethylaminonaphthalene-1- sulphonyl)amino]undecanoic acid) and 3-[p-(6-phenyl)-hexa-1,3,5-trienyl]phenylpropionic acid, showed no significant difference in binding affinities for the different mutant proteins, although maximum fluorescence values were decreased for F3W and increased for C69W. These findings were confirmed by studies of DAUDA displacement by oleate. Protein-denaturation studies in the presence of urea indicated subtle differences for the three mutants which could be explained by multiple unfolding pathways. Fatty acid binding increased tryptophan fluorescence emission in the case of the F18W protein, but had no effect on the F3W and C69W proteins. Fluorescence quenching studies with 2-bromopalmitate showed that a fatty acid carboxylate is close to the tryptophan in the F18W protein. Energy-transfer studies showed that the fluorescent moiety of DAUDA is equidistant from the three mutated amino acids and is bound within the beta-clam solvent cavity of liver FABP. This interpretation of the fluorescence quenching and energy-transfer data supports the difference in ligand orientation between intestinal and liver FABP observed in previous studies.
| S-EPMC1138240 | biostudies-other
Project description:Recent advances in the characterization of fatty acid-binding proteins (FABPs) by NMR have enabled various research groups to investigate the function of these proteins in aqueous solution. The binding of fatty acid molecules to FABPs, which proceeds through a portal region on the protein surface, is of particular interest. In the present study we have determined the three-dimensional solution structure of human heart-type FABP by multi-dimensional heteronuclear NMR spectroscopy. Subsequently, in combination with data collected on a F57S mutant we have been able to show that different fatty acids induce distinct conformational states of the protein backbone in this portal region, depending on the chain length of the fatty acid ligand. This indicates that during the binding process the protein accommodates the ligand molecule by a "selected-fit" mechanism. In fact, this behaviour appears to be especially pronounced in the heart-type FABP, possibly due to a more rigid backbone structure compared with other FABPs, as suggested by recent NMR relaxation studies. Thus differences in the dynamic behaviours of these proteins may be the key to understanding the variations in ligand affinity and specificity within the FABP family.
| S-EPMC1221651 | biostudies-literature
Project description:RationaleLipid metabolism contributes to the formation of obesity-related glomerulopathy (ORG). Heart-type fatty acid binding protein (H-FABP or FABP3) is involved in lipid metabolism and was predicted to relate to renal lesions in obesity.MethodsA total of 28 patients with ORG were investigated, and renal tissue from 7 kidney donors served as controls. Db/db mice with albuminuria were treated with Simvastatin for 12 weeks.ResultsImmunohistochemistry demonstrated the H-FABP staining in glomerular and tubular areas of patients with ORG, and the percentage of H-FABP in the glomerular area was significantly higher than in controls (15.8±1.62 versus 4.51±0.56%, P<0.001). Moreover, H-FABP expression correlated with proteinuria, high-density lipoprotein (HDL) cholesterol, waist circumference and the homeostatic model assessment - insulin resistance (HOMA-IR) among patients with ORG. Enhanced expression of H-FABP was also detected in the db/db mice, and expression increased from 8 to 20 weeks of age and was weakly related to increased albuminuria (r = 0.433; P = 0.020). Furthermore, H-FABP was co-localized with synaptopodin and demonstrated a podocyte pattern distribution. After Simvastation treatment, the urine albumin levels decreased with lipid levels and H-FABP expression in the glomeruli. The expression of H-FABP was related to Simvastatin treatment, albuminuria and triglycerides, while it was only linked with triglycerides and albuminuria (r = 0.643, P = 0.036).ConclusionsThis study confirmed an association of H-FABP with the pathogenesis of clinical and experimental ORG, and suggests that such a process might be related to podocytes and lipid dysmetabolism.
| S-EPMC3445507 | biostudies-literature
Project description:To investigate the prognostic value of heart-type fatty acid binding protein (H-FABP) in patients with stable coronary heart disease (SCHD). A total of 1,071 patients with SCHD were prospectively enrolled in this Taiwan multicenter registry study, followed for 24 months. The cut-off value of H-FABP, 4.143 pg/mL, was determined using receiver operating characteristic curves. The primary cardiovascular (CV) outcome was composite CV events, defined as cardiovascular or cerebrovascular death, myocardial infarction (MI), stroke, angina related-hospitalization, PAOD-related hospitalization and heart failure. Secondary outcomes included CV or cerebrovascular death, nonfatal MI, nonfatal stroke, and acute heart failure-related hospitalization. We found that the high H-FABP group had more than a two-fold higher rate of primary CV outcomes than the low H-FABP group (32.36% vs. 15.78%, p < 0.001). Eleven patients (4.82%) of the high H-FABP group died during the 24 months of follow-up, compared to only one patient (0.12%) in the low H-FABP group. The acute heart failure-related hospitalization rate was also significantly higher in the high H-FABP group (3.5% vs. 0.95%, p < 0.005). The results remained significant after adjusting for baseline covariates. In conclusion, H-FABP was an independent predictor for CV outcomes in the patients with SCHD, mainly in CV death and acute heart failure-related hospitalization.
| S-EPMC6158177 | biostudies-literature
Project description:Postoperative atrial fibrillation (POAF) is common and associated with poor outcomes. Perioperative ischemia can alter arrhythmic substrate.To demonstrate an association between perioperative measurements of heart-type fatty acid binding protein (HT-FABP), a sensitive marker of ischemic myocardial injury.Blood samples from 63 inpatients undergoing coronary artery bypass surgery, valve surgery, or both were obtained before and up to 4 days after surgery. Continuous telemetry monitoring was used to detect POAF. Fifty-nine patients had at least 3 HT-FABP measurements. The relationship of enzyme-linked immunosorbent assay-measured HT-FABP with POAF was assessed by using joint logistic regression adjusted for age and surgery type.Thirty-five patients (55%) developed POAF; these were, on average, older (69.3±10 years vs 60±11 years; P = .0019), with a higher prevalence of heart failure (43% vs 17%; P = .034), chronic obstructive lung disease (26% vs 4%; P = .017), preoperative calcium channel blocker use (29% vs 7%; P = .031), and more likely to undergo combined surgery (21% vs 11%, P = .049). The joint age- and coronary artery bypass surgery-adjusted model revealed that postoperative but not preoperative HT-FABP levels predicted POAF (coefficient 1.9±0.87; P = .03). Longer bypass time, prior infarction, and worse renal function were all associated with higher postoperative HT-FABP.A greater rise of HT-FABP is associated with atrial fibrillation after cardiac surgery, suggesting that ischemic myocardial damage is a contributing underlying mechanism. Interventions that decrease perioperative ischemic injury may also decrease the occurrence of POAF.
| S-EPMC3687792 | biostudies-literature
Project description:Long-chain fatty acids (FAs) with low water solubility require fatty-acid-binding proteins (FABPs) to transport them from cytoplasm to the mitochondria for energy production. However, the precise mechanism by which these proteins recognize the various lengths of simple alkyl chains of FAs with similar high affinity remains unknown. To address this question, we employed a newly developed calorimetric method for comprehensively evaluating the affinity of FAs, sub-Angstrom X-ray crystallography to accurately determine their 3D structure, and energy calculations of the coexisting water molecules using the computer program WaterMap. Our results clearly showed that the heart-type FABP (FABP3) preferentially incorporates a U-shaped FA of C10-C18 using a lipid-compatible water cluster, and excludes longer FAs using a chain-length-limiting water cluster. These mechanisms could help us gain a general understanding of how proteins recognize diverse lipids with different chain lengths.
| S-EPMC4471613 | biostudies-literature
Project description:AimsFew biomarkers to evaluate pathophysiological changes in extra-cardiac tissues have been identified in patients with heart failure (HF). Fatty acid-binding protein 1 (FABP), also known as liver FABP, is predominantly expressed in the liver. Circulating FABP1 has been proposed to be a sensitive biomarker for liver injury. However, little is known about the potential role of FABP1 as a biomarker for HF.Methods and resultsMeasurements of serum FABP1 and echocardiography were performed in subjects with compensated HF (n = 162) and control subjects without HF (n = 20). Patients were prospectively followed-up for a composite outcome of all-cause mortality or HF hospitalization. Compared with control subjects, levels of FABP1 were elevated in HF patients [7.9 (6.4-11.7) vs. 17.6 (10.4-28.9) ng/mL, P < 0.0001]. There were significant correlations between FABP1 levels and estimated right ventricular systolic pressure and right atrial pressure. During a median follow-up of 12.0 months, there were 55 primary composite endpoints in the HF cohort. The highest FABP1 tertile was associated with a three-fold increased risk of the composite outcome compared with the lowest tertile [95% confidence interval (1.46-6.68), P = 0.003], but other conventional hepatobiliary markers did not predict the outcome. After adjusting for age, sex, atrial fibrillation, and N-terminal pro-B-type natriuretic peptide levels, serum FABP1 remained independently associated with the outcome. Adding FABP1 to the model based on clinical factors and N-terminal pro-B-type natriuretic peptide significantly improved the prognostic value (global χ2 20.8 vs. 15.5, P = 0.01).ConclusionSerum FABP1 levels are elevated in compensated HF patients, and the magnitude of elevation is independently associated with pulmonary hypertension, right atrial hypertension, and worse clinical outcomes. FABP1 may serve as a new potential biomarker for the assessment of hitherto unrecognized derangement of cardio-hepatic interaction in HF.
| S-EPMC8006713 | biostudies-literature