  We generalize to five distinct flavors the flavor-spin hyperfine interaction
introduced previously for four flavors and used in the study of
$uudc\overline{c}$ pentaquark. As a particular case here we study the lowest
states of the pentaquark $uudb\overline{b}$, of either positive or negative
parity, in a constituent quark model with linear confinement and the presently
extended hyperfine interaction. The positive parity states have one unit of
angular momentum located in the subsystem of four quarks and are described by
translationally invariant states of orbital permutation symmetry $[31]_O$ which
requires the configuration $s^3 p$. The negative parity states are described by
the configuration $s^4$ of permutation symmetry $[4]_O$. We show that the
lowest state has the quantum numbers $J^P$ = $1/2^+$ or $3/2^+$ and I = $1/2$
and is located below the $\Sigma_b B$ threshold by - 132 MeV. We present a
comparison between the spectra of $uudc\overline{c}$ and $uudb\overline{b}$
pentaquarks.
