Two-dimensional NMR experiments have been performed on a peptide, succinyl-AE-TAAAKFLRAHA-NH2, related to the amino-terminal sequence of ribonuclease A. This peptide contains 50-60% helix in 0.1 M NaCl solution, pH 5.2, 3 degrees C, as measured by circular dichroism. NOESY spectra of the peptide in aqueous solution at low temperatures show a number of NOE connectivities that are used to determine the highly populated conformations of the peptide in solution. Short-range dNN(i, i + 1) and d alpha N(i, i + 1) connectivities and medium-range d alpha beta(i, i + 3) and d alpha N(i, i + 3) connectivities are detected. The pattern of NOE connectivities unambiguously establishes the presence of helix in this peptide. The magnitudes of the 3JHN alpha coupling constants and the intensities of the dNN(i, i + 1) and d alpha N(i,i + 1) NOEs allow the evaluation of the position of the helix along the peptide backbone. These data indicate that the amino terminus of the peptide is less helical than the remainder of the peptide. The observation of several long-range NOEs that are atypical of helices indicates the presence of a high population of peptide molecules in which the first three residues are distorted out of the helical conformation. The absence of these NOEs in a related peptide, RN-31, in which Arg 10 has been changed to Ala, suggests that this distortion at the amino-terminal end of the peptide arises from the formation of a salt bridge between Glu 2 and Arg 10.(ABSTRACT TRUNCATED AT 250 WORDS)

The interest in fatty-acid-binding proteins has produced about 1000 research papers since their discovery nearly 30 years ago. This review provides an entry to the mammalian and nonmammalian literature through a compendium of categorized review articles (nearly 60). Publications that have not yet been reviewed, particularly of function and modes of action, are presented and discussed in light of earlier reports. This large protein family may be integral in the relationship between lipid and carbohydrate metabolism.

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Three analogs of bradykinin containing p-2-thienyl-~-alanine in place of Phe were synthesized by the solid phase method: [3-thienyIalanine]-, [8-thienylalanine] -, and [.3,8-bis(thienylalanine)] bradykinin. These analogs were more active than bradykinin in the rat uterus and rat blood pressure assays.

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